ISSN:0003-2654    

DOI:10.1039/AN94772FX013

出版商:RSC    

年代:1947

数据来源: RSC

ISSN:0003-2654    

DOI:10.1039/AN94772BX015

出版商:RSC    

年代:1947

数据来源: RSC

ISSN:0003-2654    

DOI:10.1039/AN94772BP017

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction APRIL, 1947 THE ANALYST Vol. 72, No. 853 PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS HE Annual General Meeting of the Society was held at 3.30 p.m. on Friday, March 7th, 1947, in the meeting room of the Royal Society, Burlington House, London, W.1. The chair was taken by the President, Dr. G.W Monier-Williams. The Financial Statement for 1946 was presented by the Hon. Treasurer and approved and the Auditors for 1947 were appointed. The Report of the Council for the year ending March, 1947 (see pp. 131-137) was presented by the Hon. Secretary and adopted. The following were elected Officers and Council for the coming year. President-Lewis Eynon, B.Sc., F.R.I.C. Past Presidents serving on the Council-F. W. F. Arnaud, Bernard Dyer, E. B. Hughes, G. Roche Lynch, S. Ernest Melling, and G. W. Monier-Williams. Vice-Presidents-R. C. Chirnside, D. W. Kent- Jones, (Mrs.) J. W. Matthews and, ex oficio, C. H. Manley (Chairman, North of England Section), and H. Dryerre (chairman, Scottish Section). Hon. Treasurer-G. Taylor. Hon. Secretary-K. A. Williams. Other Members of CounciZ-C.A. Adams, R. Belcher, H. E. Cox, (Miss) I. H. Hadfield, J. H. Hamence, J. Haslam, A. D. Mitchell, J. R. Nicholls, Norman Strafford, R. W. Sutton, H. N. Wilson, E. C. Wood and, ex oficio, Arnold Lees (Hon. Secretary, North of England Section), and R. S. Watson (Hon. Secretary, Scottish Section). After the business outlined above had been completed the meeting was opened to visitors, and the retiring President, Dr: G. W. Monier-Williams, O.B.E., M.C., M.A. , F.R.I.C., delivered his Presidential Address, in which he made reference to some outstanding features in the affairs of the Society during his tenure of the presidency, and then proceeded to a consideration of certain aspects of food law administration with particular reference to the control of the use of preservatives and the presence of injurious substances in foods (see pp. 137-142). NEW MEMBERS Richard Ralph Appleby, B.Sc. (Lond.) ; Geoffrey Browne, B.Sc.(Lond.), F.R.I.C. ; Stanley James Bush, A.R.I.C. ; Terence John Cahill, F.R.I.C. ; (Miss) Eileen Mary Chatt, B.Sc. (Lond.), F.R.I.C. ; Thomas Morton Clark, B.Sc. (Lond.) ; Harry Kenneth Dean, B.Sc., Ph.D. (Liv.), F.R.I.C.; John Arthur Eggleston, B.Sc. (Lond.), A.R.I.C.; Charles Arthur Hallas, B.Sc.(Lond.) , F.R.I.C. ; Wynford Price Jones, A.R.I.C., Ph.C. ; Ralph William Latter, 13.S~. (Lond.), A.R.I.C. ; George Frederick Longman, B.Sc. (Lond.), F.R.I.C. ; Thomas Barton Mann; John Vernon Morris, B.Sc. (Lond.), A.R.I.C. ; Geoffrey Padget, Assoc.Met. (Sheff.) ; Arthur Edward Pickford, A.R.I.C. ; Joseph Brian Rickson, B.Sc. (Lond.), A.R.I.C. ; Albert Arthur Smales, BSc. (Lond.), A.R.I.C. ; William Stross, M.D. (Prague) ; Cyril Gordon Sumner, M.Sc., Ph.D. (Manc.), A.R.I.C.; Leslie Stuart Theobald, M.Sc. (Lond.), A.R.C.S., F.R.I.C.; Walter Frederick Wilkinson, M.P.S.

ISSN:0003-2654    

DOI:10.1039/AN947720129a

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C.Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner.He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction April, 19471 ANNUAL REPORT OF COUNCIL: MARCH, 1947 131 Annual Report of Council: March, 1947 THE roll of the Society numbers 1345, an increase of 75 over the membership a year ago.The Council regrets to have to record the death of the following members: H. G. Battye J. J. Blackie G. E. Boizot A. Bruce J. L. Buchanan W. J. A. Butterfield W. R. Dracass G. W. Edwards H. Firth J. A. Foster P. F. Frankland C. D. Garbutt A. D. Heywood E. Hinks P. H. Jones J. F. Liverseege T. McGrath R. S. Morrell M. Nierenstein F. E. Needs W. H. Roberts K. H. Vakil G. H. Warburton S. Watkinson Battye, who died in his 58th year, was elected a member of the Society in 1940. He studied at the Central Technical College and Leeds University, and after being engaged in private practice for some years he went to Canada.In 1941 he became an Inspector of Explosives and was subsequently a chemist in the Department of Mines, Ottawa. Boizot, who died at the age of 33, received his scientific training at Battersea Polytechnic and obtained the B.SG. degree with first class honours. He was subsequently employed by May & Baker, Ltd., and in 1931 became Food Analyst to United Dairies, Ltd. In 1938 he132 ANNUAL REPORT OF COUNCIL: MARCH, 1947 [Vol. 72 was appointed Assistant Government Analyst at Singapore. He died in 1943 whilst a prisoner of war. Bruce, who died in his 69th year, was elected a member of the Society in 1925. He studied at Edinburgh University and obtained the B.Sc.degree in 1900. After a short period of service at the Royal Arsenal, Woolwich, he went to Ceylon and engaged in con- sulting and analytical practice. He published a number of papers and became a Fellow of the Royal Society of Edinburgh. Buchanan, who died at the age of 73, became a member of the Society in 1923. He worked for some years in the laboratory of Tatlock, Readman and Thomson, City Analysts, Glasgow. In 1894 he joined Messrs. Lever Bros. at Port Sunlight, became a Managing Director in 1911 and, in 1922, Chairman of the Associated Company, John Knight, Ltd. Butterfield, who died in his 80th year, had been a member of the Society for 43 years. He received his scientific training at Oxford, obtaining the B.A. degree with honours in chemistry and subsequently M.A.In 1891 he became chemist to the Gas Light and Coke Co., Beckton, and afterwards a Gas Referee under the Board of Trade, and in 1938 Advisor to the Board of Trade under the Gas Undertakings Act, 1934. He was also engaged in con- sulting practice. He served for two periods as an Ordinary Member of the Council of the Society and, in 1920-21, as Vice-president. Dracass, who died in his 37th year, was elected a member of the Society in 1933. He studied at King’s College, London, where he graduated B.Sc. in 1930, and at the Sir John Cass Technical Institute, obtaining the M.Sc. degree in 1935. He worked for some years in the laboratory of the late Mr. E. Hinks, then with Messrs. Burroughs, Wellcome & Co., and in 1944 he.became Senior Analyst to Dr. H. E.Cox until, shortly before his death, he became employed by Allied Supplies, Ltd. Edwards, who died in his 26th year, was elected a member of the Society in 1944. He was trained at the Manchester College of Technology and was for 8 years an assistant analyst to Messrs. Melling & Ardern. In 1943 he was appointed as a chemist to the War Department. He received his scientific training at Bradford Technical College. After some years of analytical ex- perience he became Senior Analyst to Lipton, Ltd., and later, Chemist to C. & T. Harris (Calne), Ltd. In 1937 he became Manager of the Food Cannery of Messrs. J. Travers & Son. After a period of service as Second Assistant Admiralty Chemist he became Public Analyst for the East Riding of Yorkshire, Grimsby, Beverley and Louth, Official Agricultural Analyst for Grimsby and Gas Examiner for Lincolnshire. Frankland, who died at the age of 88, was elected an Honorary Member in 1909.He occupied the Chairs of Chemistry at University College, Dundee, and Birmingham, succes- sively. He was elected President of the Institute of Chemistry in 1906 and of the Chemical Society in 1911, and was awarded the Davy Medal of the Royal Society in 1919. Heywood, who died in his 57th year, had been a member of the Society for 35 years. After studying at University €allege, London, and long experience in analytical. work he was appointed head of the laboratory of Messrs. Courtaulds, Ltd., Castle Works, Flint, and subsequently Technical Manager at $he Wolverhampton works of the same firm.Hinks, who died in his 67th year, had been a member of the Society for 41 years. He received his scientific. training at King’s College, London, and obtained the B.Sc. degree. He became assistant to Sir Thomas Stevenson, Home Office Analyst and Public Analyst for Surrey, succeeding to the latter appointment on Stevenson’s death. He subsequently held a number of other appointments and was also engaged in private practice. For his services as an officer in the Army Ordnance Corps during the 1914-18 war he was awarded the M.B.E. He served on the Council of the Society continuously from 1911 until his death, first as an Ordinary Member, then as Honorary Treasurer, then as President (in 1928-29), and finally as Past President. Having qualified as a pharmacist, he attended University College, Liverpool, and qualified as A.I.C.in 1894. He became asistant to Professor Campbell Brown and subsequently senior assistant analyst to Professor W. H. Roberts, Public Analyst to the City of Liverpool. He published numerous papers on the microscopy of starches and spices. Liverseege, who died in his 83rd year, had been a member of the Society for 53 years. He was trained at University College, Nottingham, and Mason College, Birmingham. In Firth, who died in his 46th year, became a member of the Society in 1926. Foster, who died in his 75th year, had been a member of the Society for 46 years. (Obituary, ANALYST, 1946, 71, 347.) Jones, who died in his 84th year, was elected a member of the Society in 1930.April, 19471 ANNUAL REPORT OF COUNCIL: MARCH, 1947 133 1885 he became assistant to the City Analyst for Birmingham and succeeded to that appointment in 1902, retiring in 1929.Morrell, who died in his 80th year, became a member of the Society in 1920. From Bradford Grammar School he went to Gonville and Caius College, Cambridge, in 1886. After a period at Wurzburg he returned to his College as a Fellow in 1896 and retained his Fellow- ship until 1904; then he went to Mander Bros., the well-known paint and varnish manu- facturers at Wolverhampton, and retained the position of Chief Chemist until 1930. Needs, who died in his 63rd year, was elected a member of the Society in 1934. He was trained at the Merchant Venturers Technical College and Bristol University. For some years until 1914 he was assistant to the Public Analyst for Bristol and during the war of 1914-18 served in the R.E.and R.F.A. After that war he became Senior Assistant in the Bristol Corporation Laboratory and in -1930 was appointed Public Analyst for Bristol. Roberts, who died in his 69th year, had been a member of the Society for 35 years. He graduated at Victoria University and subsequently took the MSc. degree. He became City Analyst for Liverpool at the age of 34 and held many other Public Analyst appointments and the Associate Professorship in Public Health Chemistry at Liverpool University. He served the Society as Ordinary Member of the Council, Vice-president in 1934-5 and President in 1938-9. Watkinson, who died at the age of 60, was elected a member of the Society in 1943.He worked at first in the laboratory of the late Mr. A. H. Allen, and in 1916 went to the Great Central Laboratory, Gorton, Manchester. In 1925 he was moved to Doncaster as a result of the railway amalgamation and was District Chemist there until his retirement. ORDINARY MEETINGS-Five meetings of the Society were held during the year and the following papers were communicated : “The Determination of Boron.’’ “Separation of the Cobalt Complex of Nitroso-naphthol from other Coloured Metallic “Exhibition and Description of Apparatus : (Obituary, ANALYST, 1947, 72, 36.) By E. C. Owen, B.A., M.Sc., Ph.D. Complexes.” By E. Boyland, D.Sc. 1. For the Control of Delivery from Burettes. 2. A Vacuum-operated Circulating Pump. 3. A Thermostatically-controlled Low-Temperature Bath.4. For the Continuous Production of Doubly Distilled Water.’’ By-J. T. Stock, M.Sc., F.R.I.C., and M. A. Fill. I. The Assay of Tryptophan, Leucine, Isoleucine, Valine, Cystine, Methionine, Lysine, Phenylalanine, Histidine, Arginine and Threonine.” 11. The Distribution of Amino Acids in the Wheat Grain.’’ By E. C. Barton-Wright, D.Sc., F.R.I.C., and T. Moran, D.Sc., Ph.D. By G. G. Freeman and R. I. Morrison. Part I-The Estimation of Water by an Improved Fischer Method.” “The Microbiological Assay of Amino Acids. By E. C. Barton-Wright, D.Sc., F.R.I.C. “The Microbiological Assay of Amino Acids. “The Determination of Some Products Qf Sugar and Molasses Fermentations.” “The Estimation of the Volatile Matter Content of Propellant Explosives. By T. G. Bonner. “The Analysis of Barium Carbide.” “The Fundamental Laws of Polarography.” By J.Heyrovsky, D.Sc., Ph.D. “Reductometric Determination of the Sulphoxide and Amine Oxide Groups.” By Mrs. “The Determination of the Composition and Constitution of Ammonium Phosphomolybdate By W. P. Thistlethwaite, B.Sc., The December Meeting was a Joint Meeting with the Food Group of the Society of The subject was “The Application of Statistical Methods to Food By A. H. Edwards. Erica Glynn. and the Conditions affecting its Precipitation.” A.R.I.C. Chemical Industry. Problems,” and the following papers were read and discussed: Introductory Address : “The Inevitability of Statistics.” “The Use of Statistical Analysis in Research on Food Canning.” By D. J. Finney, M.A. By W. B. Adam, M.A., F.R.I.C.134 ANNUAL REPORT OF COUNCIL: MARCH, 1947 [Vol.72 “The Evaluation of the Nutritive Value of Animal Feeding Stuffs.” By Dr. K. L. Blaxter. “Application of Statistical Methods in Calculating Proportions of Ingredients in Certain RULES OF SECTIONS AND GRouPs-The Rules of Sections and Groups, prepared by the Special Committee appointed for that purpose, were approved by the Council and issued to all members of the Society with the December number of THE ANALYST. The following papers have been read: “A Photoelectric Method of Assaying Vitamin A in Margarine.” By J. L. Bowen, N. T. Gridgeman, B.Sc., and G. F. Longman, B.Sc., F.R.I.C. “The Determination of Carotene and Vitamin A in Butter and Margarine.” By T. W. Goodwin, M.Sc., A.R.I.C., and Prof. R. A.Morton, Ph.D., D.Sc., F.R.I.C. “An Application of Photoelectric Spectrophotometry to the Analysis of Mixtures.” By Prof. R. A. Morton, Ph.D., D.Sc., F.R.I.C., and Dr. L. A. Stubbs. “The Determination of the Pyridine Content of Technical Pyridine.” By A. Hamer, B.Sc., A.R.I.C., R. Pomfret, A.R.I.C., and W. V. Stubbings, B.Sc., A.R.I.C. “The Rapid Determination of Sodium in 50 Per Cent. Potassium Hydroxide Liquor, 50 Per Cent. Potassium Carbonate Liquor and Solid Potassium Carbonate.” By J. Haslam, M.Sc., F.R.I.C., and J. Beeley. “The History of Chocolate and Sugar Confectionery.” By Dr. L. E. Campbell, F.R.I.C. “The Determination of Traces of Lead, Zinc and Tin in Phenol.” By W. Hutchinson and “Soil Biochemistry.’’ By Dr. H. Lees, BSc., A.R.I.C. Food Products.’’ By E.H. Steiner, B.Sc., A.R.I.C. NORTH OF ENGLAND SECTIOW-Four meetings have been held during the year. H. N. Wilson, F.R.I.C. There have been good attendances at the meetings. The Hon. Secretary wishes to express his appreciation of the loyal support and assistance accorded to him by the Chairman, Vice-chairman and members of the Committee during the year. SCOTTISH SECTION-Three meetings were held during the year, one of them jointly with the Physical Methods Group, at which the following papers were presented and discussed : “Determination of Vitamins A and A, by Photoelectric Spectrophotometry with some “Modern Aids to Spectroscopy.” By B. S. Cooper, B.Sc., F.1nst.P. “Application of. Spectrographic Analysis to Soil Investigations.” By Dr. R. L. Mitchell. “Spectrographic Analysis of Rare and High Purity Materials.” By D.M. Smith, A.R.C.S., {‘Semimicro Method for the Determination of Magnesium.” By James A. Hunter, B.Sc. “Some Observations on the New Ice Cream Order.” By C. W. Herd, Ph.D., BSc., F.R.I.C. The total membership remains the same as for the previous year, viz., sixty-four. MICROCHEMISTRY GROUP-TWO meetings were held during 1946, one in London and one in Cardiff. The latter was held jointly with the Cardiff and District Section of the Royal Institute of Chemistry and the South Wales Section of the Society of Chemical In- dustry. It was also intended to hold a meeting in Birmingham during September, but owing to circumstances beyond control the arrangements had to be cancelled. remarks on General Principles.” By Professor Morton and Dr.A. L. Stubbs. . B.Sc., F.1nst.P. The following papers have been read: “Chemical Microscopy in Metallurgical Analysis. ” Miss I. H. Hadfield. “A Review of Methods for the Micro Analysis of Gazz” By W. A. Kirby. “Determination of Cyanide by the Picrate Method: A Water-bath for Heating Simul- By J. G. A. Griffiths and J. K. Whitehead. “Some Observations on the Kjeldahl Method for the Determination of Nitrogen.” By “Methods for the Construction of Microchemical Apparatus.” Three meetings will be held in 1947. taneously many Tubes of Reactants.” A. E. Beet. By R. Belcher. These include the Annual General Meeting, held in London in January, a meeting a t Sheffield in May, and it is hoped a meeting at Cambridge jointly with the Physical Methods Group in September. The number of Group members is now 181, an increase of 21 since the last Report.April, 19471 ANNUAL REPORT OF COUNCIL: MARCH, 1947 135 Activities of the Committee-The Committee has met three times during the year.Following the proposal made at the last Annual General Meeting, British Intelligence Ob- jectives Service was asked if a team could be sent to Germany and Austria to report on advances in microchemical methods made during the war. The matter was referred to the Department of Scientific and Industrial Research who agreed to sponsor such a team, and the Committee was invited to make nominations for the team. It was hoped that the trip would take place in September, but it has been postponed several times. The delays are stated to have been due to other bodies demanding representation on the trip, and it is now expected that two teams will travel.The report on educational institutions teaching microchemistry, prepared by Dr. Cecil L. Wilson, has been published in Nntwe and reprints have been circulated to all members. A census has also been taken of industrial laboratories using microchemical methods ; Dr. Wilson kindly undertook the task at the request of the Committee. A report is now being prepared. PHYSICAL METHODS GROUP-During the past year the activities of the Physical Methods Group have expanded considerably. The policy announced last year has been continued and each meeting of the Group has taken the form of a symposium on a particular physical method of analysis. Two meetings have been held in London and one each in Edinburgh and Cardiff.The Edinburgh meeting was held jointly with the Scottish Section of the Parent Society and the Cardiff meeting jointly with the Cardiff and District Section of the Royal Institute of Chemistry and the South Wales Section of the Society of Chemical Industry. All the meetings were well attended. The following papers were read at meetings of the Group : Barker Index Meeting in London on November 28th, 1945. “The Barker Index.” By R. C. Spiller. “The Utility of the Barker Index in Analytical Chemistry.” A. E. J. Vickers. “General Principles. ” “Partition Chromatography.” “Chromatography in the Analysis of Fatty Oils.” “Some Applications of Chromatographic Analysis in Industry.’’ By F. R. Cropper. Spectroscopic Analysis Meeting in Edinburgh on May 23rd, 1946.“Photoelectric Spectrophotometry Applied to the Analysis of Mixtures and Vitamin A By R. A. Morton and A. L. Stubbs. “Modern Aids to Spectroscopy.” By B. S. Cooper. “Applications of Spectrographic Analysis to Soil Investigations. ” “Spectrographic Analysis of Rare and High Purity Materials.” By D. M. Smith. Electrometric Analysis Meeting in Cardiff on October l l t h , 1946. “Recent Developments in Apparatus for pH Measurements and Electro-titrations. ” By “Some Applications of Electrometric Methods to Analysis.” “Polarisation End Points.” The Publication Committee of the Parent Society has decided to publish in booklet form the proceedings of some of the Group meetings. The booklets covering the Polarography, Chromatography and Spectroscopy meetings will be available shortly.In May, Dr. F. Wokes resigned from the office of Honorary Secretary and the Committee appointed Dr. J. E. Page to succeed him. The sincere thanks of the Group are due to Dr. Wokes for all the work that he has done since the inception of the Group. The objects of the Panel will be to hold and sponsor informal discussions on polarographic analysis. The Committee of the Panel will be elected at the forthcoming Annual General Meeting of the Group. The Group has been represented on the Vitamin Sub-Committee of the Analytical Methods Committee by Mr. G. F. Lothian and Dr. F. Wokes and on the Barker Index Com- mittee by Dr. J. G. A. Griffiths, Dr. J. H. Hamence and the Honorary Secretary. The number of the Group members is now 148, an increase of 20 since the last Annual General Meeting.By M. W. Porter and Chromatographic Analysis Meeting in London on January 26th, 1946. By F. A. Robinson. By R. L. M. Synge. By K. .A. Williams. Oils.” By R. L. Mitchell. A. D. E. Lauchlan. By R. J. Carter. By D. P. Evans. The Committee of the Group has formed a Polarographic Discussion Panel.136 ANNUAL REPORT OF COUNCIL: MARCH, 1947 [Vol. 71” BIOLOGICAL METHODS GROUP-In the Report of the Provisional Committee which was presented at the first Annual General Meeting of the Group on February 25th last it was stated that the Committee was considering a Draft of Rules for the constitution and conduct of the Groups of the Society which had been put forward for consideration by the Council.A final version of these Rules has now been agreed upon and has been sent to every member of the Group. I t is provided in these Rules that the Annual General Meeting of the Bio- logical Methods Group shall be held in December of each year, and it will therefore be con- venient for the business year to end on the 30th November. This Report, therefore, covers the period from the first Annual General Meeting up to the 30th November, 1946. During this period two meetings have been held. The Annual General Meeting was followed by an Ordinary Meeting at which Messrs. N. T. Gridgeman and E. C. Feiller read papers entitled respectively “The Transformation of Metameters, with special reference to Vitamin D Assays,” and “Some Remarks on the Statistical Background of Bio-Assays.” At a subsequent meeting on the 27th May papers were read by Dr.K. Mather and Dr. G. Pontecorvo on the genetical background of bio-assays, Dr. Mather dealing with the larger animals, and Dr. Pontecorvo with micro-organisms. Both of these meetings were well attended, not only by members, but also by a number of visitors, some of whom have since joined the Society. PUBLIC ANALYSTS AND OFFICIAL AGRICULTURAL ANALYSTS COMMITTEE-The Committee met during the past year on three occasions. Recommendations have been made in respect of financial matters directly concerning Public Analysts, also in relation to definitions of cocktails and other liquors; some of the latter have since been adopted in part by the Ministry of Food. Two Bulletins have been issued to Public Analysts and a quantity of routine business transacted.ANALYTICAL METHODS COMMITTEE-RePOrtS of good progress have been received from sub-committees. The appeal published in THE ANALYST (1946, p. 300) to assist the work of the Standard Methods Committee on compilation of a bibliography met with a very satis- factory response and much progress has been made. Considerable work has been done by the Sub-committees on Vitamin Estimations, Gum Tragacanth and Determination of Metallic Impurities in Foodstuffs. The membership of the Group is now 87. Two reports from the Committee have been published during the year, viz. “The Determination of Phenols in Soaps.” “Report on the Microbiological Assay of Riboflavine and Nicotinic Acid.” ANALYST, 1946, p. 301.ANALYST, During the year the Committee lost the services by resignation of W. H. Simmons as Hon. Secretary, a position he had held since the inception of the Committee, in 1924, but he remains an active member. Mr. Simmons, whose valuable work for the Committee is greatly appreciated, has been succeeded by Dr. D. C. Garratt. Horv. TREASURER’S REPORT-The financial position for 1946 is satisfactory inasmuch as the income balances the expenditure. But it is the view of the Hon. Treasurer that, having regard to the probability of increased expenditure, due mainly to the increasing activities of the Society, and to the increasing cost of publication of THE ANALYST, it is desirable that the future commitments of the Society should now be critically examined. THE ANALYST-At the beginning of 1946 the restricted consumption of paper permitted to THE ANALYST by the Paper Control made it difficult to accommodate the increasing number of original papers offered for publication, and some restriction of space given to the other sections of the journal became necessary.Later the paper position was greatly eased by a considerable increase in the permitted consumption, granted on the ground that the journal was “primarily concerned with the first publication of original research.” The 1946 volume has 600 pages, compared with 486 in the 1945 volume and 388 in 1944. The number of original papers published in 1946 was 80, compared with 56 in 1945 and 40 in 1944. On the other hand there were only 31 Notes in 1946, compared with 45 in 1945 and 39 in 1944; but these are not a very important factor in the distribution of space in the journal.The circu- lation of the journal was greater by several hundreds in 1946 than in 1945. A new development this year is the issue, in the form of stiff-covered reprints, of certain important papers or sets of papers from THE ANALYST. Three are on the point of publication, 1946, p. 397.April, 19471 ADDRESS OF TIIE RETIRING PRESIDENT 137 viz., the Symposia of Polarography, Chromatography and Spectroscopic Analysis, respec- tively, held at the meetings of the Physical Methods Group. In consequence of the increasing quantity of matter in THE ANALYST and the need for inore efficient organisation of the Abstract section of the journal, it has been found neces- sary to augment the editorial provisions hitherto made. The Publication Committee have been fortunate in obtaining for this purpose the part-time services of Mr. F.L. Okell, F.R.I.C., as general Assistant Editor, and Mr. L. S. Theobald, M.Sc., A.R.C.S., F.R.I.C. , as Associate Editor responsible particularly for the Abstract section of the journal. EMERGENCY COMMITTEE-This Committee was appointed in September, 1938, with full power to act on behalf of the Council should a state of emergency warrant it. The Committee has met on several occasions since its appointment. The state of emergency having passed, the Committee was not re-appointed for 1946-47. CHEMICAL covNcIL-The Society has been co-opted on the Chemical Council and the President and Honorary Treasurer have been appointed as representatives of the Society on the Council. ROYAL I~sTITu'rE OF CHEJIISTKY-Dr. G. Roche Lynch, Past President of the Society, was elected President of the Royal Institute of Chemistry in March, 1946. The Council has offered its congratulations to Dr. Roche Lynch on this high distinction. BRITISH STANDARDS INSTITUTION-Dr. iv. E'. Elvidge was appointed representative of the Society on Committee C/8 and Sub-committee C/8/1B of the British Standards Institution. BUREAU OF ABSTRACTS-MI-. A. L. Bacharach was appointed a representative of the Society on a Committee of the Bureau to report on the suggestion to issue separate sets of abstracts covering both the scientific and technical aspects of foods and nutrition. INSTITUTION OF WATER ENGINEERS--I)r. J. H. Hamence and Mr. s. E. Melling were appointed representatives of the Society on a Joint Committee on the standardisation of methods of chemical analysis of potable waters. The Office of the Society is available for meetings of small committees; for the accom- modation of larger committees the Council again desires to record its thanks to organisations and to members of the Society. G. W. MONIER-WILLIAMS, President LEWIS EYNON, Hon. Secretary

ISSN:0003-2654    

DOI:10.1039/AN9477200131

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C.Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner.He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction April, 19471 ADDRESS OF TIIE RETIRING PRESIDENT 137 Address of the Retiring President G. W. MONIER-WILLIAMS, O.B.E., N.C., M.A., PH.D., F.R.I.C. IT is my privilege on retiring from the chair to address the members of this Society and I propose, with your permission, to follow the usual custom of referring shortly to some of the Society’s activities during my term of office and then discussing at greater length a subject of particular interest to many of our members.The chief events of the past two years are fully recorded irrthe Council’s annual reports, but there are a few matters to which special reference should be made. We have been most unfortunate during this period in losing three of our Past Presidents, Evans, Roberts, and Hinks, to all of whom the Society owes a great debt of gratitude for the work they did for us. Edward Hinks was for many years honorary treasurer before succeeding to the chair, and the value of his work for the Society can hardly be over-estimated. I personally used often to consult him on difficult or controversial matters concerning our profession and could always count on getting thoroughly sound and practical advice.He was ready at all times to take the utmost trouble in the service of the Society, and there have been few whose influence in our Council was greater or whose loss has been more deeply felt. Roberts and Evans also had been active in promoting the interests of the Society and were particularly associated with the work of the North of England Section. I cannot let this occasion pass without expressing the great pleasure we feel in Dr. Bernard Dyer’s continued presence among us. We were able the other day to congratulate him on his 91st birthday, and I can assure him, on behalf of every member of the Society, that we are138 ADDRESS OF THE RETIRING PRESIDENT [Vol. 72 extremely proud of our distinguished original member and grateful to him for the close and practical interest which he continues to take in the affairs of the Society.The past year has been remarkable for the success which has attended the proceedings of the three subject groups. The Microchemical Group under the chairmanship of Professor Briscoe, the Physical Methods Group under Mr. Chirnside, and the Biological Methods Group under Mr. Bacharach, have been ably guided through the hazards of infancy and have become firmly established as active and progressive members of the analytical body. In the coming years the problem of chemical publications is bound to become more and more acute, and the task of our Publication Committee, under Dr. Nicholls, in maintaining the high standard and reputation of THE ANALYST, will become still more exacting.A particu- larly difficult problem is that of abstracts of papers published in other journals. Our policy is to select our material very carefully over the whole range of analytical chemistry and to make the abstracts full enough to be of real value in the laboratory. This policy makes increasing demands upon the skill and judgment of the editorial staff. We have lately en- larged this staff considerably, and I think we may feel confident that they will prove fully equal to the task before them. In this matter of abstracts we shall be wise to co-operate closely with other publishing bodies, and members of our publication committee have already held preliminary discussions on this subject with representatives of the Bureau of Abstracts. Another important step in the direction of co-operation is the co-option of the Society to membership of the Chemical Council, a position which secures to us a voice in matters of general policy and administration.The Public Analysts Committee, under the chairmanship of Dr. Cox, recently drafted recommendations on terms and conditions of appointment, for issue by the Council to local authorities. These recommendations have gained sympathetic response and improved conditions in a number of cases, but many authorities still seem unwilling or unable to recog- nise the heavy responsibility and exacting nature of the work and the long scientific training required. With the emphasis now laid upon sound nutrition as the basis of health, a highly qualified and efficient public analyst service, working under conditions which will attract the ablest men, will become of ever greater importance to the country.With the end of the war the Analytical Methods Committee has again become active. Some valuable reports have been published, notably one on the microbiological determination of riboflavine and nicotinic acid. A sub-committee is also engaged on a bibliography of published approved and standard methods, which should be extremely useful to analysts in this country. The thanks of the Society are due to Dr. Hughes and his colleagues on the committee, and also to the members of the many sub-committees, for the immense amount of arduous voluntary work which they give so willingly. The reports of this Committee con- tribute very greatly to the high reputation of THE ANALYST both in this country and abroad.We have been concerned during the past two years with the teaching, or, as some would say, the lack of teaching, of analytical chemistry in university courses. This is a very difficult question and perhaps we, as analysts, run the risk of being accused of undue bias. We may remember, however, that our illustrious former honorary member; Professor Fresenius of Wiesbaden, in the introduction to his well-known book on chemical analysis, emphasises the fact that “chemistry owes to quantitative analysis its elevation to the rank of a science.” Further he says that “quantitative analysis forms the strongest and most powerful lever for chemistry as a science, and nbt less so for chemistry in its applications to the practical purposes of life, to trades, arts and manufactures.” I am sure that the truth of these words, written over 70 years ago, is recognised by those responsible for chemical education in this country.Many of us feel, however, that more attention should be given to the systematic teaching of accurate quantitative analysis. Perhaps in these days of overloaded undergraduate courses the answer to the question is to be found in Professor Fresenius’ further observation that “the pursuit of this branch of chemistry requires considerable expenditure of time.’’ I should like to take this opportunity of thanking those who replied so fully to my inquiries upon this subject. Their views have been submitted for consideration to the Chemistry Education Advisory Board, and there are indications that they may meet with a favourable response.The year 1945 saw the end of the war and it would have been appropriate for me to have attempted a comprehensive survey of the impact of the war years upon this Society and its work, such a survey as was given in a masterly way by Dr. Samuel Rideal a t the end of the previous war. Even from the food standpoint alone, however, it would be difficult to doApril, 19471 ADDRESS OF THE RETIRING PRESIDENT I39 justice to this theme. One would have to deal with foad substitutes, food standards, food labelling, the contributions of analytical chemistry to the solution of nutrition problems- all the scientific and administrative activities of the last seven years which have added so greatly to the work and responsibilities of the public analyst.Perhaps it will be more useful if, instead of attempting to cover such a wick field, I make some observations, and I hope some constructive observations, upon one aspect of food administration which has not received much attention during the war. In all food legislation we can distinguish two distinct and separate objects, firstly the promotion of fair trading without any particular health significance other than that of adequate nutrition, and secondly the protection of the public against possible injury to health from harmful stlbstances. It is this latter object that I want to discuss-the prevention of risk to health from questionable substances which may gain access to food during its preparation, storage or treatment.Under Section 8 of the Food and Drugs Act of 1938, power was given to the Minister of Health to make regulations prohibiting or restricting the addition of any substance to food and regulating generally its composition. In 1943, under the Defence (Sale of Food) Regula- tions, similar powers were given to the Minister of Food, but it is not quite clear from the wording of the regulations, or of the explanatory White Paper, which of these Ministers was expected to take action where contamination is concerned. Practically all the orders made by the Minister of Food during the war have been concerned with fair trading or adequate nutrition. There has been some relaxation of the Preservative Regulations of 1925, and quite recently an order concerning edible gelatin, but with these exceptions no orders con- trolling potentially toxic substances in food have been made either under the 1938 Act or under the Defence (Sale of Food) Regulations.I t seems doubtful whether this purely health function will in future be discharged by the Ministry of Health or whether it will be handed over to the Ministry of Food, as appears to have been done with edible gelatin and with fluorine in acid calcium phosphate. Whichever department is ultimately responsible for control of this kind there are, I think, three main principles which should govern any action taken. If we set out to devise limits of tolerance for toxic substances in food, the chief considera- tion, obviously, is the effect on health of the small quantities in question, and here we meet with the first and greatest difficulty-what is to be regarded as injurious to health? Owing to the complexity of the processes taking place in the body and the extreme difficulty of relating cause and effect, there is usually a very wide range between that which can be accepted without question as being harmless and that which can be shown conclusively to be injurious.A limit might be fixed anywhere within this range and the claim made that the consumer had been adequately protected. There are many people concerned with the chemistry of food and nutrition who deprecate the placing of any restraint upon trade in these matters unless it can be clearly shown to be necessary in order to prevent injury to health and who hold strictly to the experimental method.If any limit is set for a toxic substance they would put it high in this doubtful range on the ground that there is no experimental evidence that the substance in question is in- jurious in that amount. At the other extreme there are many who think that any suspicion that a substance may be injurious, even to a minority of the less resistant persons, should be enough to warrant its exclusion altogether from food. They would condemn any treatment of food which may involve the slightest contamination with questionable substances. As an example of the difficulty of deciding what is or is not injurious we may take lead. We have first to consider what is the safe daily intake of lead on the assumption that it is all absorbed, for this will affect the safety limits for different foods.In spite of the long ex- perience gained with water supplies this point is not yet definitely settled. Some people are more susceptible than others to lead poisoning, women for instance much more so than men. The effects of lead are cumulative: even when ingested in minute amounts it can be stored in the body and again become active under different conditions of health and of dietary habits. Then again there is the difficultyeof recognising with certainty the milder forms of lead poisoning. Some authorities hold that it is responsible for many anomalous nervous conditions and slight ill health. On the other hand it seems that many people who come into contact with lead industrially may excrete it in relatively large amounts and yet show none of the recognised symptoms of lead poisoning.Its ultimate effects may not be evident for several years.140 ADDRESS OF THE RETIRING PRESIDENT [Vol. 72 When we have arrived at some conclusion as to the limit which should be set for the amount of lead absorbed into the system over any given period we have still to consider what proportion of the lead in food is actually so absorbed. Water, beer and cider seem to give it up much more readily than solid foods. In particular a high intake of calcium in the diet hinders absorption; from foods-rich in milk or dried milk, lead, if present, is absorbed only slightly. Phytic acid, also, and pectin may combine with lead and remove it from solution, and there are probably other constituents of food which have a similar effect.Absorption of lead may thus depend to some extent upon the nature of the food, and even upon the sequence of different foods, from day to day. These are problems for the physiologist, the nutrition specialist and the chemist together, but even the most expert team would be hard put to it to prepare a schedule of limits for lead in different foods which would be free from criticism. A similar uncertainty applies more or less to other potentially toxic substances in food; for instance, antimony or zinc, certain azo dyes as colouring matters, thio-urea as an antioxidant, or methyl bromide as a fumigating agent. Methyl bromide in small doses over a long period has been found to hinder the growth of animals. Can we disentangle from the multitude of factors affecting growth in human beings a possible slight effect due to the use of methyl bromide for fumigating food and its retention by fat? Ho~7 are we to say at what point a contamination or treatment of food loses its harmless character and becomes suspect ? The Minister of Health has often been asked to give a ruling on specific cases but has rarely, if ever, done so.There is a clear distinction between giving an interpretation of the meaning of the word “injurious” in Section 1 of the Act, which is the prerogative of the Courts, and embodying that interpretation in a regulation under Section 8, which is the privilege of the Minister. Section 7 of the Act lays it down that any addition to food which has been forbidden by regulations is ips0 fncto to be regarded as injurious to health, which seems to solve the problem quite neatly, but unfurtunately regulations are always several laps behind public health requirements. The object of Section 7 is, presumably, to uphold the regulations in a possible conflict of expert evidence.I am not aware of any similar pro- vision in respect of orders made under the Defence (Sale of Food) Regulations. This Society, in a memorandum submitted to the Departmental Committee on the Composition and Description of Food, urged the setting up of a permanent statutory advisory committee consisting of representatives of the Ministry of Health, public analysts, manu- facturers and consumers which, among other duties, “should on request state definitely with regard to any ingredient of a food, the interpretation of the term ‘injurious to health’.” This suggestion, possibly for the reasons I have given, was not favoured by the Departmental Committee, which made an alternative recommendation that any controversial question on which an order is applied for should be referred to an ad hoc committee of three independent persons for public inquiry and report.Neither of these suggestions has been adopted. There seems to be a tendency now to refer these questions to the Medical Research Council, but I doubt whether this is the proper body to deal with them. In difficult and contentious matters of this kind the first instinct of the administrator is to compromise, but we may question whether this instinct is sound- where food is concerned. One need not elaborate the fact that food is in a category altogether different from that of any other commodity. We are bound to take into consideration the chances of remote action beyond the reach of experimental proof and to insist upon a wide margin in favour of the consumer.The proper course is to ensure that, within the range in which doubt exists as to the toxicity of any substance in food, the limit of tolerance shall be placed at the lowest possible point, and this, I suggest, should be regarded as a first principle. It is precisely that lack of knowledge, that difficulty of experimental proof, which should make us chary of compromising in this matter. If this principle is accepted, and if we have succeeded in defining the doubtful range in respect of a particular substance, we have to decide what are the very lowest limits within that range which can reasonably be insisted upon as a practical measure.It must be re- membered that food manufacture, packing and distribution are by no means confined to large concerns with ample resources for regular scientific control. Many of the smaller concerns find it hard to keep a constant check on raw materials and to maintain a consistently high standard. In deciding upon appropriate limits we must consider carefully what can be reasonably demanded in all circumstances. I do not suggest for a moment that there should be any allowance for inefficiency; rather that every endeavour should be made to discoverApril, 19471 ADDRESS OF THE KETIKIXG PRESIDENT 141 what can and what can not be done by different types of producers working under different conditions.It may be that a requirenent which seems at the time impossible of fulfilment will act as a stimulus to improvement and will soon become normal practice. It is of course very difficult to arrive at a sound conclusion. The necessity for careful and detailed inquiry 1:as been recognised by successive departmental committees. In the old days of the Foods Department of the Local Government Board, and later of the Ministry of Health, someone with the requisite experience was detailed to investigate and report on a particular con- tamination or treatment of food as fully as possible, by visits to factories and by making contact with anyone who could give trustworthy information on the subject. Probably this method, in the hands of a competent investigator, gets at the facts more surely than the alternative one of taking evidence from, and cross-exanining, interested parties at a com- mittee table.The Interdepartmental Committee on Preservatives in 1923-24 employed both methods, and the subsequent regulations were the result of as full an inquiry as was possible with the limited staff available Even so, several points were missed but, considering the wide field covered by the inquiry, this was perhaps inevitable. We may remember that the Royal Commission on Arsenical Poisoning, whose report stands out as a model of thorough and exhaustive investigation, failed to appreciate the partiality of shell-fish for arsenic. i’vly second principle then, although it sounds self-evident, is that, when it has been decided on health grounds that control is necessary, the fullest possible investigation should first be made of all the comrpercial factors involved. This implies of course that an adequate staff should be made available for the purpose, but nowadays one hesitates to suggest any further addition to the public service.When a decision has been reached on the practical limits to be adopted for any foreign substance in a particular food or foods there remains the question whether these limits or prohibitions should be embodied in regulations, or whether there is any other way of securing their acceptance by the trade and by those concerned with administration. Statutory standards have an immense advantage from the viewpoint of administrative convenience and greatly simplify the whole procedure of Food and Drugs Act work.They are also a safeguard for the manufacturer and distributor, who thus know exactly where they stand and are not so liable to become involved in unforeseen litigation. On the other hand it is very difficult, when framing regulations, to take every factor into account, and clearly impossible to make adequate allowance for changing circumstances. Legal standards have the disadvantage that they are not readily altered and may remain in force long after scientific research and industrial progress have made them virtually obsolete. Nominally it should be an easy matter to amend a regulation-and this is one of the advantages claimed for departmental regulations as compared with Acts of Parliament-but in practice it has proved difficult, even when the weight of evidence has been overwhelmingly in favour of amendment.I am not speaking, of course, of war-time orders which have to deal quickly with constantly changing conditions The third principle, therefore, is that any regulations on food matters must allow of ready revision, not only in theory but in practice, as unforeseen contingencies arise. A common charge against standards is that they tend to become the normal and that while they may induce a general levelling up of poor quality articles there is also a tendency to a levelling down of the better qualities, to the disadvantage of the consumer. If, however, we are able to place the limit for a toxic substance low enough, this objection loses much of its force.Another objection, of course, is the instinctive dislike of official interference in our daily lives. The experience of the last six years has not made us anxious for further restric- tions. It will be agreed, I think, that no standard of the type we are discussing should be imposed unless a reasonable case has been made out for it on health grounds. There is always a danger that a demand for standards may be prompted more by a desire for adminis- trative convenience than by health considerations. There has been much criticism of government by shoals of departmental regulations having the force of law, and it is worth while considering whether in certain- cases official pronounce- ments or recommendations might carry enough weight to make such regulations unnecessary.Arsenic provides a case in point. The limits proposed for arsenic in food by the Royal Commission over forty years ago have never yet been given statutory force except for edible gelatin, and yet they have been accepted without serious question for administrative purposes. In fact the absence of a rigid standard has on occasions been undeniably convenient, as for instance when arsenic of natural origin was discovered in fish and more recently in parsley. of supply.142 HERON: THE OXIDATION OF NITROGEN DURING THE [Vol. 72 Would similar pronouncements in respect of other potentially injurious substances in food, backed by a sufficient weight of authority, be accepted in the same way as the arsenic limits? I very much doubt it.The recommendations of the Royal Commission followed a serious and widespread outbreak of poisoning in Lancashire , and the general acceptance of the limits then proposed was due more to the shock of that occurrence and the fear of further trouble than to the authority of Lord Kelvin and his colleagues on the Commission. The questions of lead, copper, and antimony, of preservatives and colours, of flavouring vehicles, of fumi- gating agents, and of antioxidants are more controversial and less clear cut than that of arsenic, and the possible effects on health are not nearly so spectacular. The report of the Depart- mental Committee on Preservatives, a body just as competent as the Royal Commission to decide the health question, would have had little influence on the use! of preservatives if its findings had not been crystallised into regulations.The report by itself would undoubtedly have been of assistance to those whose task it is .to interpret the meaning of the word “in- jurious” in the Act, and indeed several of the Local Government Board and Ministry of Health reports have been pf great value in this way; but the regulations and standards which followed the findings of the Preservatives Committee have had a definite and salutory effect on the quality of food in this country and on the conditions under which it is prepared and stored. Moreover, it is doubtful whether any advisory body would give sufficiently close attention to these problems, especially the more controversial of them, if their advice was to be treated only as an opinion to be contested and possibly over-ruled. Such advice would have to be clefinitely associated with a proposal for an order or regulation. In the absence of statutory standards certain administrative methods have been adopted with more or less success to secure some sort of control. Thus medical officers at the ports, using their powers under the Imported Food Regulations, agreed a few years ago on limits for toxic metals in some imported foods. The importer could, of course, appeal to the Courts if he felt aggrieved, but in practice he seldom did so. This Society has, in a few instances, formulated its own standards, and local authorities often bring pressure to bear upon manu- facturers and distributors to accept certain criteria of purity in respect of particular foods. These isolated efforts only touch the fringe of the problem. During the recent period of stringency and short supply many things have of necessity been tolerated which will demand careful reconsideration on return to more normal conditions. It is clear that if any con- tamination or treatment of food is suspected of being in any way injurious, the consumer’s interest demands that it should be effectively regulated. Public analysts have always been insistent upon this. At present they are in the invidious position of having, in the first instance, to apply their own standards in order to carry out their duties under the Act. They are justified in asking that they should be relieved of this responsibility and that it should be undertaken by some department of State through an advisory body combining the necessary scientific, commercial and administrative experience and authority. In conclusion, I should like to express my thanks to the officers, council, and members of this Society for the kindness and consideration which they have at all times shown to me, and to accord to you, Mr. President, my best wishes for your term of office.

ISSN:0003-2654    

DOI:10.1039/AN9477200137

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C.Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner.He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction 142 HERON: THE OXIDATION OF NITROGEN DURING THE [Vol. 72 The Oxidation of Nitrogen during the Micro- Combustion of Organic Substances BY A. E. HERON (Read at the Annual General Meeting of the Microchemistry Group 09% January 31st, 1947) ACCORDING to Preg1,l amino, imino, and similar compounds yield on combustion, in addition to carbon dioxide and water, elementary nitrogen, or at the most, nitrous oxide.In their paper on “A New Technique for the Ultimate Micro Analysis of Organic Compounds,” Belcher and Spooner2 state that it depends on how the nitrogen is combined whether or not oxides of nitrogen are formed, but recommend the use of a bubbler containing acid dichromate or permanganate, with all compounds containing nitrogen, until information is available as to which compounds do and which do not form oxides of nitrogen. In March, 1944, we were comparing the standard macro- and the Pregl micro-method for the analysis of coal, and found that the results obtained with 5- to 7-mg. samples andApril, 19471 MICRO-COMBUSTION OF ORGANIC SUBSTANCES 143 Pregl’s method were not greatly divergent from those obtained with 150-mg.samples by the standard macro-method. The results obtained with a modified form of the combustion technique described in the paper referred to,2 but without the chromic and sulphuric acid bubbler, were all somewhat higher than those obtained by our standard macro-method. These results were published in J . Inst. F u ~ Z , ~ and the suggestion was made that the discrep- ancy might be due to retention, by the reagent in the carbon dioxide absorption tube, of oxides of nitrogen produced from the nitrogen contained in the coal. It was subsequently shown that oxides of nitrogen could be readily detected in the products of combustion of a 5-mg. sample.Analyses of the same sample of coal when a bubbler containing chromic and sulphuric acids was used gave results that agreed tolerably well with those obtained by the Pregl micro- and our standard macro-method. In all the experiments on the micro scale the sample was burned in a platinum boat. In the method of Belcher and Spoone? for the rapid simultaneous determination of carbon, hydrogen, sulphur, and chlorine in coal, on the macro scale, samples are burned in a rapid stream of oxygen at a temperature of 1300” C. No special provision is made for the removal of oxides oi nitrogen, for, according to the authors, under the conditions employed, no oxides of nitrogen are formed, the nitrogen being evolved completely as elementary nitrogen gas.3 Thus, although the influence of nitrogen on the macro scale is apparently insignificant, our results suggested that the effect of nitrogen on the micro scale was important and required further investigation. In a private communication, Belcher stated that he had carried out some experiments on the macro scale, using porcelain and platinum boats to contain the sample of coal, and had found that if platinum was used oxides of nitrogen could be detected in the products of com- bustion, but that he could find none when porcelain was used.He also said that tests on the micro scale, with use of a train packed with silica chips, such as we were using in our modi- fication of the unpacked tube technique, indicated that nitrogen oxide formation could be detected to a small extent when coal was burnt in a porcelain boat, and more readily when a platinum boat was used.It was thought that the problem should be investigated quantitatively and that the results obtained by examining the products of combustion of various nitrogen-containing organic substances would be of real value. According to I<i~-ner,~ “oxidation of the nitrogen- containing thermal decomposition products by the excess of oxygen present in the combustion tube at temperatures from 600” C. down to 180” C. would yield only nitrogen peroxide and nitrogen. The proportion of these two substances which finally results under a given set of conditions should primarily be a function of the manner in which the nitrogen is linked in the molecule.” The purpose of our investigation was therefore to find out how much oxidation of nitrogen occurs during the combustion of compounds containing nitrogen.The determination of the extent to which this occurs resolves itself into the finding of a suitable absorbent, the oxidation of the absorbed gas, and the evaluation, by a suitable method, of the nitrate produced. EXPERIMENTAL The silica combustion tube was of the usual type with side arm; it was heated by an electric furnace giving a temperature of 1000” C. at the centre. Toward the exit end of the tube was a 2i-inch roll of silver gauze, so placed that about half of it was heated directly by the furnace winding. The exit end of the tube was heated by a copper block, maintained a t 130” to 160” C. to prevent condensation of water. In some of the experiments the portion of the tube that was heated in the furnace was packed with silica chips, but in others the tube was free from packing. For the deter- mination of the “oxides of nitrogen’’ it was decided to use a colorimetric method which depended upon the nitration of an organic compound, rather than upon an oxidation effect as does the diphenylamine test.Soda asbestos as used for the carbon determination was tried as absorbent for the nitrogen peroxide, but replicate tests for nitrate on weighed amounts gave widely different results. It was found that when the gases were passed through a spiral bubbler containing sodium hydroxide solution, absorption of carbon dioxide was not complete; it could be detected in the gases after they had passed through the spiral bubbler.A vacuum technique was also tried by means of which all the gases obtained during the com- bustion could be submitted to the action of an absorbent solution. Heavy walled bottles of about 750 ml. capacity were obtained and each fitted with a rubber bung carrying a single-way tap, the end of which was gradually tapered to the same diameter as the exit of the combustion tube. When a determination was to be made, a small volume of suitable absorbent was A pre-heater packed with silica chips was used.144 HERON: THE OXIDATION OF NITROGEN DURING THE [Vol. 72 measured into a bottle, which was then evacuated with a good water-pump, and connected to the train. The rate of flow of oxygen was controlled by adjustment of the tap fitted to the bottle. In the earlier experiments a bubble-counter was used to indicate the rate of flow of oxygen, but later a White - Wright flow meter6 was substituted.This is a recognised absorbent for nitric oxide and nitrogen peroxide. After the gases had been in contact with this solution for 3 hours, it was acidified with 20 per cent. sulphuric acid and warmed to about 40" C. for 15 minutes to oxidise nitrite. Hydrogen peroxide was then added to destroy the excess of permanganate and followed by a slight excess of sodium hydroxide. The sample was now boiled and filtered, and the filtrate evaporated to dryness. Two ml. of a 1.25 per cent. solution of sulphosalicylic acid in 50 per cent. sulphuric acid were added and the solution was heated on a water-bath for 30 minutes. It was then diluted, 25 ml.of 10 per cent. sodium hydroxide solution were added, the volume was made up to 50ml. and the optical density was measured on the Spekker absorptiometer a t 4360~. In a number of tests trouble was experienced owing to precipitation of manganese after the final addition of sodium hydroxide, and the blank values obtained were not consistent. A similar lack of agreement on control tests was observed when the absorbent used was 80 per cent. sulphuric acid containing sulpho- salicylic acid. It is possible that in this case there was some carbonisation of the reagent. When this reagent is used, the nitro com- pound may be steam distilled from the solution in which it is formed , and thus separated from substances that might interfere with the measurement of its optical density.At the same time, in order to reduce the number of reagents employed to a minimum and to keep the technique as simple as possible, it was decided to use as absorbent ceric sulphate in sulphuric acid, a reagent which rapidly oxidises nitrite to nitrate at room temperature. With these modifications to the method, there was no difficulty in obtaining agreement in blank tests. The procedure was as follows- The electric furnaces were switched on and the temperature of the copper block adjusted. The oxygen flow was adjusted to a rate of about 35 ml. per minute. Three ml. of 0.1 N ceric sulphate solution in 12 per cent. sulphuric acid were measured into the vacuum bottle, which was evacuated by means of a good water pump, and connected to the train., The weighed sample was then introduced into the combustion tube and this was securely stoppered with the rubber bung.The tap of the vacuum bottle was cautiously opened until a rate of flow of oxygen of 25ml. per minute was indicated by the bubbler or flow meter. The sample was then burned off and the products of combustion swept forward in the usual way, the oxygen rate being maintained at 25 to 30 ml. per minute throughout, by adjustment of the tap. At the end of twenty minutes the tap was closed and the bottle discmnected from the train. The in-let tube was washed with 2 ml. of 20 per cent. sulphuric acid without removal of the stopper from the bottle, the contents of which were still under slightly reduced pressure. The bottle was then rotated frequently over a period of 1 hour, and at the end of this time the stopper was removed.0.2 N Ferrous sulphate was added till the colour of the ceric sulphate was just discharged, and then followed a dropwise addition of 0.1 N potassium permanganate until a barely perceptible pink colour was obtained. The pennanganate, of which only 1 or 2 drops are required, was used as an indicator, ceric sulphate itself not being sufficiently intensely coloured. Five ml. of a 1 per cent. solution of 2:4-xylenol in dilute sodium hydroxide solution were added, followed by 35ml. of sulphuric acid of sp.gr. 1-76. The temperature while this was being added was not allowed to exceed 35" C. ; the solution was a t this temperature for 30 minutes.. At the end of this time the contents of the bottle were washed into a steam distillation apparatus, with approximately 150 ml.of water. The nitro compound and excess of 2:4-xylenol were distilled into 1 ml. of N sodium hydroxide. The distillate was made up to a given volume and its optical density determined on a Spekker absorptiometer. The mercury lamp was used with Chance No. 6 and Wratten No. 50 filters (4360~). RECOVERY OF NITROGEN- Dinitrobenzene was burned, the products of combustion were collected and the oxides of nitrogen formed determined as described above. Five determinations were made, two with a boat of fireclay, and three with a boat of platinum. The tube contained only the silver coil. The results are given in Table I. This and the subsequent tables show the conditions of each experiment, the weight of sample taken and the quantity of "oxides of nitrogen," calculated as NO,, which was collected in the ceric sulphate solution.This is also shown as a Alkaline permanganate was first tried as absorbent. The use of 2:4-xylenol was then considered.April, 19471 MICRO-COMBUSTION OF ORGANIC SUBSTANCES 145 percentage of nitrogen on the sample. Finally the proportion of nitrogen collected as NO, is shown as a percentage of the total nitrogen present. TABLE I COMBUSTION OF DINITROBENZENE, 16.7 PER CENT. N Wt. of Expt. sample Fire;lay ,* 6.376 Combustion tube contained only 7.045 silver coil. Oxygen rate 25 to Platinum 7.310 30 ml. per min. 8.678 I J ' 8.960 No. Conditions of test Boat mg- 3 ) Nitrogen absorbed Calc. Calc. as Calc. as as mg. N % of N % of NO, sample total N 3.29 15-7 94.2 3.75 16.2 97.2 3.88 16.1 96.6 4.54 15.8 94.8 4-06 13.7 82-2 I A \ These results were considered satisfactory for the purpose of this investigation and the method was used for all the subsequent work.THE COMBUSTION OF COAL- A sample of Craghead coking coal which contained 1-26 per cent. of nitrogen, as deter-- mined by the Kjeldahl method, was used for the work on coal. Weighed amounts of this sample were burned under different conditions, and the results are recorded in Table 11. Oxides of nitrogen were produced in all experiments. The results when the tube was packed TABLE 11 COMBUSTION OF CRAGHEAD COKING COAL, 1.26 PER CENT. N Conditions of test Boat I J ) ,J Tube packed with silica chips and containing silver coil. Oxygen rate 25 to 30 ml./min.I * J 1 j J c J J CFireclay above. { Plaiinum l i No silica chips, otherwise as I j ' t J J Weight of sample mg- 10-843 9.822 9.864 10.022 10-412 10-466 9.749 10.822 12.240 9.640 10.050 8.654 10.068 10.083 9.843 10-039 9.840 10.422 9.642 10.625 10.053 10.383 10-545 9.842 Nitrogen absorbed Calc. Calc. as Calc. as asmg. N% of N yo of B02 sample total N 0.105 0.30 23.8 0.039 0.12 9.5 0.063 0.19 15.1 0.066 0.20 15.9 0.049 0-15 11.9 0.095 0-28 22-3 0.079 0.25 19.9 0.102 0-28 22.3 0.151 0-38 30.2 0.098 0.31 25.0 0.066 0.20 15.9 0.049 0-18 13.5 0.043 0-13 10.3 0.085 0.26 20.6 0.138 0.38 30.2 0.121 0.37 29.4 0-128 0.40 31-4 0-135 0.39 30.9 0.068 0.22 17.5 0.061 0.19 14.3 0.032 0.10 7.9 0.059 0.17 13.5 0.106 0.31 24.6 0.049 0.15 11.8 I A 3 with silica chips and contained the silver coil ranged from 9.5 to 30-2 per cent., when the boat was of fireclay.When the platinum boat was used, the results ranged from 10.3 to 31.4 per cent. In each case the distribution of results was fairly even over the whole range. When the tube contained only the silver spiral, the results with the porcelain boat ranged from 7.9 to 17.5 per cent. and with the platinum boat from 11.8 to 24-6 per cent. It is of interest that W. R. Kirner,' in a series of experiments for the direct simultaneous micro-determination of carbon, hydrogen, and oxygen in coal, found that correct oxygen values were obtained when it was postulated that 59 per cent. of the nitrogen present was converted into nitrogen peroxide and 41 per cent. to elemental nitrogen. This figure for nitrogen peroxide is much higher than any of the results we have obtained.146 HERON: THE OXIDATION OF NITROGEN DURING THE [Vol.72 COMBUSTION OF PURE ORGANIC COMPOUNDS- Table I11 shows the results of combustions carried out on various pure organic com- pounds : (a) carbazole, (b) pyridine, (c) xylidine, (d) dimethylaminoazobenzene (dimethyl yellow) and (e) urea. With all of them oxides of nitrogen were formed in variable amounts. Carbazole, for example, yielded from 7.4 to 32.2 of its total nitrogen as oxides and there was TABLE I11 COMBUSTIOX OF PURE ORGAKIC COMPOUNDS Nitrogen absorbed I A % Expt. No. 33 ::-I 34 351 :;} 367 37 I 38 r 39 J 427 43 k 44J 457 46 k 47 J 487 49 I 50 r 51 J 52 7 53 k 54J 557 56 1 57 r 58J 61 r :I '62 J Weight of Calc.sample as mg. Conditions of test Boat "€5 NO2 (a) COMBUSTION OF CARBAZOLE, C6H4.NH.C6H,, 8.4% N I I Fireclay 10.328 0.490 9.851 0.259 8.502 0.756 8.306 0.665 1 Platinum 8.511 0.598 10.522 0-216 Fireclay 10.310 0.484 12.780 0.319 Platinum 10.560 0.484 #, 11.890 0.298 and boat with sample. Tube contained only boat with 10.497 0-362 sample. {Zzk: 10.287 0.328 i II Tube packed with silica chips and containing silver coil and boat with sample. Tube contained only silver spiral :: (b) COMBUSTION OF PYRIDINE, C,H,N, 17.7% N Tube packed with silica chips Fireclay 10.684 1.260 and containing silver coil and Platinum 6.990 0.415 8.690 1.015 10.420 0.756 8.116 1-882 {;;2m 5.424 0.684 boat with sample. . { J ) Tube contained silver coil and boat with sample. (C) COMBUSTION OF XYLIDINE (CH,),C6H,NH2, 11.5% N Tube packed with silica chips ll'loo 0.342 8.624 0.495 9.961 0.645 10.727 0.529 and containing silver coil and boat with sample.J 1' Calc. as N% of sample 1.43 0.80 2-70 2-44 2.14 0.62 1.40 0.76 1-39 0.74 1-04 0-98 3.60 1.80 3.58 2.20 7.08 3.84 0.94 1.75 1-96 1.50 (d) COMBUSTION OF DIMETHYL YELLOW, C&,N : N.C,H,N(CH,),, 18.65% 1-54 1.98 Tube containing silver coil and 7'504 0*379 6.760 0.551 Pla&um 8.520 0.437 1.98 boat with sample. (e) COMBUSTION OF UREA, CO(NH,),, 46.6% N 1.31 1.07 9'186 0'349 11.045 0.402 9.900 0-414 1.27 8-765 0.609 2.11 Tube packed with silica chips and containing silver coil and boat with sample. Fireclay 10.740 0.168 0.48 12.928 0.312 0-73 Pla&um 11.701 0.282 0.73 { J ) 9-854 0-175 0.54 Tube contained silver coil and boat with sample.Calc. i s NYo of total N 17.0 9.5 32.2 29.2 25.4 7.4 16.7 9.1 16.5 8.8 12-4 11-7 20.3 10-3 20.2 12.5 40.0 20.5 8.1 15.2 17.0 13-1 8-3 10.6 10.6 2-8 2.3 2.8 4.6 1.0 1-6 1.6 1.2 no marked difference in the order of magnitude of the results according as fireclay or platinum boats were used. With pyridine, again, the results show no marked differences attributable to any particular condition in the tests. Dimethyl yellow contains two types of nitrogen linkage, viz., C.N:N.C and C.N/'. The amounts of nitrogen oxides formed from urea were consistently small. One result amounting to 48 per cent. of the total nitrogen was obtained, but as this figure was not approached in any subsequent test it has been rejected \cApril, 19471 .MICRO-COMBUSTION OF ORGANIC SUBSTANCES 147 Finally, several experiments were carried out in which air was passed through the train with a platinum or fireclay boat in position. With a platinum boat the results obtained when 500 ml. of air were passed along the tube at a rate of 25 to 30 ml. per minute showed that oxides of nitrogen equivalent to 0-01 to 0.02 mg. of NO, were produced and that when fireclay boats were used the results varied between 0.003 and 0.01 mgm. It should be added here, that the control tests on reagents and blank tests for the combustions in oxygen were deducted in every case, in the calculation of results. DISCUSSION- The investigation has shown that when compounds of different types containing carbon, hydrogen and nitrogen are burned in a stream of oxygen, appreciable amounts of oxides of nitrogen are produced.The results obtained from the combustion of coal indicate that although the material used for the boat may have some effect, it is of minor importance, and the effect of the surface provided by the silica chips is somewhat greater. In the written discussion on the papers by Zelcher and Fenton on “Methods for the Determination of Carbon and Hydrogen in Coal and their Practical Utility”3 results obtained on the same sample of coal by the B.S. method8 and the open tube technique* are quoted by Edwards and Vahrman. These results are in substantial agreement, but it should be noted that in neither of these methods is special provision made for the removal of oxides of nitrogen from the products of combustion, and thus it is unsound to deduce from these results that oxidation does not occur.Oxidation to the extent indicated in Table I1 would result in the carbon values being high by approximately 0-9 times the amount of nitrogen absorbed (i.e., from 0.11 to 0.36 per cent.). An error of this magnitude would be of no special signifi- cance in the analysis of coal. The subordinate effect of the silica packing can also be traced in the results obtained by the combustion of the pure organic compounds, but with these the effect of replacing the fireclay boat by one of platinum was not marked. The oxidation of the nitrogen probably takes place at the instant ’of ignition. The,rapidity with which a given weight of sample is consumed is not easy to control as it is influenced by several factors, e g ., the thickness and length of the layer in the boat and the temperature of the tube at the instant of ignition. These factors may be responsible for the variation in the results obtained on each compound. Up to 40 per cent. of the total nitrogen may be oxidised during the combustion. Kirner,5 who used a combustion tube packed with copper oxide, states that in cases where nitrogen is linked to hydrogen and carbon, the conversion to nitrogen peroxide is 26 per cent. and for nitriles, heterocyclic nitrogen compounds and nitro compounds, the conversion is 59 per cent. Our results indicate that for the amino compounds examined oxidation may vary between 1 and 17 per cent. of the total nitrogen, and for heterocyclic compounds the range lies between 7 and 40 per cent.This represents less conversion of nitrogen to nitrogen dioxide than Kirner’s work suggests should take place when this type of compound is burned in oxygen. For dinitrobenzene the amount of nitrogen dioxide absorbed represented between 82 and 97 per cent. of the nitrogen present, a much higher value than that quoted by Kirner. Our experiments amply confirm Pregl’s statement1 that “metallic silver is quite un- suitable for the reliable absorption of the nitrogen oxides,” but we have not confirmed his statement that “amino and similar compounds yield on combustion elementary nitrogen only, or at most possibly nitrous oxides.” It is evident that if carbon and hydrogen are to be determined on organic substances containing amino, heterocyclic, diazo or nitro nitrogen provision must be made to remove oxides of nitrogen from the products of combustion, when combustions are carried out on the micro scale.SUMMARY- Experiments on the micro scale have been performed to determine the extent to which oxides of nitrogen are produced when organic compounds containing carbon, hydrogen, and nitrogen are burned in oxygen. Almost the whole of the nitrogen present in nitro compounds is recovered as oxides of nitrogen; when nitrogen is not linked to oxygen, between one and forty per cent. of the total is oxidised. Thus, when carbon and hydrogen are to be determined on compounds containing nitrogen on the micro scale, provision must be made to remove oxides of nitrogen completely from the products of combustion.148 HERON: THE OXIDATION OF NITROGEN DURING THE [Vol.72 REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. Pregl, F., 2nd English Edn., p. 32. Beicher,. R., and Spooner, C. E., J . Chem. Soc., 1943, p. 313. Written discussion on papers by Belcher, R., Fenton, G. W., and Spooner, C . E., J . Inst. Fwel, Belcher, R. , and Spooner, C. E., Fuel, 1941 , 20, 130. K h e r , W. R., Ind. Eng. Chem., Anal. Ed., 1935, 7 , 366. White, E. V., and Wright, G. F., Canad. J . Research, 1936, 14, 427. Kirner, W. R., Ind. Eng. Chem., Anal. Ed., 1936, 8, 57. B.S. Methods for Analysis and Testing of Coal and Coke, No. 1016, 1942. 1944, 18, Suppl., p. 51. IMPERIAL CHEMICAL INDUSTRIES, LIMITED BILLINGHAM DIVISION RESEARCH DEPARTMENT, ANALYTICAL LABORATORY BILLINGHAM, Co. DURHAM October, 1946 DISCUSSION Mr.R. BELCHER said that Mr. Heron's investigation constituted a valuable contribution to our knowledge of the behaviour of nitrogen-containing compounds when burnt in oxygen. He felt, however, that much still remained to be explained. The combustion technique used by Mr. Heron was one of a series of methods that have been developed, using what was called the "empty-tube" technique. The first of these methods to be developed was that for the simultaneous determination of sulphur and chlorine in coals (A. E. Beet and R. Belcher, Fuel, 1940, 19, 42). This was a macro method using 0.5 to 1.0 g. of sample. In the initial stages of the work it was assumed that nitrogen oxides would be formed from oxidation of the nitrogen in the coal, and a titrimetric method was sought that would be specific for the sulphate ion, rather than an alkalimetric method, because it was believed that nitric acid would be formed.Since none of the titrimetric methods for sulphate examined was reliable it was decided to test whether or not nitrogen oxides were formed when the coal was burnt under these conditions, that is, in an empty porcelain tube a t a temperature of 1350" to 1400" C. No trace of nitrogen oxides was detected by qualitative tests with the brucine reagent. In the method finally adopted sulphur oxides and chlorine were absorbed in hydrogen peroxide to give sulphuric and hydrochloric acids respectively. After determination of the total acidity, chloride was determined titrimetrically and the sulphur figure found by the difference between the two readings.Since the results gave good agreement with the B.S. methods, further evidence- although indirect-was thus supplied that nitric acid was absent, for otherwise the results would have been high. That there was no loss of chlorine or sulphur oxides, compensated by nitric acid absorption was shown by carrying out gravimetric determinations for sulphate and chloride. This method had been adopted by many laboratories in the coking industry and had been recommended as a standard method for routine testing within the industry. Attention was next turned to the determination of carbon and hydrogen in coals and a macro-method in which carbon, hydrogen, sulphur, and chlorine were determined simultaneously was evolved (R. Belcher and C.E. Spooner, Fuel, 1941, 20, 130). If nitrogen oxides were . formed, one would have expected the carbon figures to have been unduly high, whereas all results were in accord with those obtained by the B.S. method. Again, this method or a modification of it was used in other laboratories, which, he believed, had satisfied themselves, both by qualitative tests and indirectly by comparing the results with those given by the B.S. method, that nitrogen oxides are not formed. This method had given so much satisfaction and possessed so many advantages over the B.S. method that the British Standards Institution was to examine it with a view to its recommendation in the standard speci- fications. So far the methods discussed were carried out on the macro-scale and only applied to coals.Later the same technique was used for the analysis of organic compounds on both the macro- and the micro-scale a t a temperature of 800" C. during the combustion. The speaker and his collaborators con- cerned themselves only with the application of the method to organic compounds and did not apply it to coals. Had they done so they would certainly have assumed that nitrogen oxide formation was non- existent, for it, was reasonable to assume that a mere reduction in the scale of working would not cause nitrogen oxide to be formed. The few nitrogen-containing compounds that were examined appeared t o bear out Pregl's statement, as quoted by Mr. Heron. When the nitrogen was already linked to oxygen, nitrogen oxides were formed. With other combinations such as an amino group, there was no evidence of nitrogen oxide formation.However, it was felt that a more thorough investigation of this aspect was required, hence the cautious statement with which Mr. Heron prefaces his account, that a buhbler con- taining an absorbent for nitrogen oxides should always be included if the compound contains nitrogen. Mr. Heron's investigation appeared to indicate that this precaution must now always be taken. It was the behaviour of coal on combustion which presented some mystery. When Mr. Heron, using the micro method of the speaker and his collaborators, first communicated his results with coal, some fundamental difference between the two scales of working was sought, because it was thought that their own evidenceApril, 19471 MICRO-COMBUSTION OF ORGANIC SUBSTANCES 149 and that of many other workers supported the view that nitrogen oxides were not formed from coal on the macro-scale or at least they were formed in negligible quantities. On the macro-scale a porcelain boat had been used, whereas Mr. Heron had used a platinum boat on the micro-scale. This seemed to be a likely cause of the differences because of the catalytic effect of the platinum. Some qualitative tests were done with coal burnt in porcelain and platinum boats, with the result that no nitrogen oxides were found in the former case, but the latter conditions showed that some formation had occurred. When the tube was packed with silica chips the formation also seemed to be enhanced slightly. Mr. Ingram carried out some similar tests a t the speaker’s suggestion and confirmed these findings as regards the effect of platinum and porcelain boats. An explanation was needed, therefore, as to why nitrogen oxides were formed when micro quantities of coal are burnt in the combustion tube, while the effect on the macro-scale is negligible. It might be that the same amount was formed regardless of the quantity of sample taken and that this amount, whilst significant on the micro-scale, was not apparent on the macro-scale. Against this, however, there were the very variable quantities that Mr. Heron found when using similar weights of coal. When the reason for this phenomenon had been explained we should have a clear picture of the whole process. As far as the various methods were concerned, the original instructions still held; namely, for coals on the macro-scale, nitrogen oxide formation could be ignored. On the micro-scale provision must always be made for removing nitrogen oxides when nitrogen-containing substances were present in a combustion. The only difference appeared to be that what the speaker and his collaborators had recommended as a pre- cautionary measure, Mr. Heron has show-n to be a necessity. Mr. G. INGRAM said that with an empty combustion tube he had found that no nitrogen dioxide was produced by burning coal in a porcelain boat, but with a platinum boat some was formed. Silica chips had but little effect ; only occasionally were traces of nitrogen dioxide produced. Organic substances containing nitro groups yielded traces of nitrogen dioxide when burnt in a porcelain boat; under the same conditions, those containing the amino group did not. With a platinum boat high carbon figures were obtained from amino compounds, showing that some nitrogen dioxide was formed.

ISSN:0003-2654    

DOI:10.1039/AN9477200142

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction April, 19471 MICRO-COMBUSTION OF ORGANIC SUBSTANCES 149 The Polarographic Determination of Tin, Lead and Zinc in Phenol BY H. N. WILSON AND W. HUTCHINSON (Read at a meeting of the North of E.lzgland Section on October 19th, 1946) IxTRoDucTIoN-Zinc, tin, and-occasionally-lead may be present in “pure” phenol, and methods are required for their determination. In manufacture the phenol is distilled, and a “block-tin” or tin-lined condenser is sometimes used, as it is known that phenol condensed in this way does not discolour so rapidly as that condensed in mild steel or iron.The phenol, whilst still liquid, is run into drums, which may be “galvanised,” or zinc-lined. The metals are present in a few parts per million, with perhaps lead and iron also. A rapid and simple method of analysis is required. Several variations of the dithizone reaction can be used for the colorimetric determination of zinc and lead, but these were found to be troublesome and slow; difficulties were also en- countered in the colorimetric determination of tin. As polarographic methods for the deter- mination of these elements have been described,1,2 it was decided to attempt to devise modi- fications suitable for our purpose. A rapid method of sufficient accuracy was worked out. This is described below, and followed by a brief description of the experimental data on which the accuracy of the method may be assessed.The quantity of iron commonly present does not interfere, and a determination of the three metals may be completed in 3 hours. The method has now been in routine use for about eighteen months, and has proved very satisfactory. METHOD REAGENTS- HydrochZoric acid, 10 per cent. w/w (sp.gr. 1.050). Hydrobromic acid A .R. containing 46 to 48 per cent. of HBr. Bromine A.R. Sodium hydroxide solution, N .150 WILSON AND HUTCHINSON : THE POLAROGRAPHIC [Vol. 72 Benzene, pure. Phenol. Gelatin, 0.1 per cent. solution in water. Tin sta.ndard soZution-Dissolve 1.00g. of pure tin in a minimum of concentrated hydrochloric acid, evaporate to low bulk and make up to 1 litre with 10 per cent.(w/w) hydrochloric acid; (1 ml. = 1.00 mg. of tin). Lead standayd solution-Dissolve 1.29g. of pure lead carbonate in a minimum of dilute hydrochloric acid, evaporate to low bulk and make up to 1 litre with 10 per cent. (w/w) hydrochloric acid. Zinc standard solzdion-Dissolve 1-00 g. of pure zinc in a minimum of dilute hydro- chloric acid, evaporate to low bulk and make up to 1 litre with distilled water; (1 ml. = 1.00 mg. of zinc.) Prepare suitable dilutions of these standards for use as required. Redistilled in glass apparatus. B.P. phenol doubly distilled in glass apparatus. PROCEDURE- Add 50 ml. of benzene, warm gently until dissolved and wash into a stoppered 250-ml. separating funnel with a further 50 ml. of benzene. Extract this solution with five separate 5-ml.portions of 10 per cent. hydrochloric acid, washing each extract twice with 20 ml. of benzene and finally collect the extracts in a 25-ml. measuring cylinder. Adjust the volume to 25 ml. with 10 per cent. hydrochloric acid. It is necessary to shake vigorously and allow to settle well between washes as traces of benzene interfere with the regularity of the tin polarogram. TIN AND LEAD-Pipette 2 or 5 ml. of the hydrochloric acid extract into a suitable polaro- graphic cell, de-oxygenate with electrolytic hydrogen for 5 minutes, adjust the sensitivity to 1/5 and make a polarogram over the voltage range -0.2 to -0.7 volt, using the mercury pool as the anode. The half-wave potential for tin and lead occurs at -0.46 volts. Measure the step height.LEAD AND zwc-Pipette 10 ml. of the extract into a 30-ml. squat beaker and evaporate carefully just to dryness on a hot plate. Add 1 ml. of hydrobromic acid and two or three drops of elemental bromine, evaporate to dryness and repeat the treatment with hydrobromic acid and bromine. This treatment completely removes tin. Cool, extract the residue four times with 1 ml. of boiling N sodium hydroxide and combine the extracts in a 10-ml. measuring cylinder. Cool the combined extracts to room temperature, add a further 1 ml. of N sodium hydroxide and one drop of 0.1 per cent. gelatin solution and make up to 10 ml. with distilled water. Pipette 2 or 5 ml. of the solution into a suitable polarographic cell, de-oxygenate with electrolytic hydrogen for five minutes, adjust the sensitivity to 1/5 and make a polarograni over the voltage range -0.5 to -0.1 volt, using a saturated calomel cell as the anode.With the same photographic paper, solution and saturated calomel cell, adjust the sensitivity to 1/10, ’reset the zero and make a polarogram over the voltage range -1.2 to -1.8 volt. Measure the step height in both instances. The half-wave potential for lead in N sodium hydroxide solution is -0.75 volt and that for zinc in the same solution is -1.50 volt. Carry out a “blank” on the reagents and deduct the step height found for any of the metals from the corresponding step height of the particular metal polarogram. The lead and zinc contents can be read direct from graphs giving the step height in alkaline solution as concentration of the respective metals.In the case of tin, dedmt the step height of the lead in alkaline solution from the combined tin and lead step height in acid solution; this gives the step height due to the tin alone, from which the tin content can then be read from the appropriate graph. A control experiment may be run on a solution containing 0.020 g. of phenol and 0.0005 g. of tin, lead, and zinc per 25 ml. of 10 per cent. hydrochloric acid, and, if necessary, a correction applied to compensate for temperature changes. This solution is equivalent to 20 parts of tin, lead, and zinc per million, when a 25-g. sample is used for analysis. Weigh 25 g. of the phenol into a 150-ml. beaker. EXPERIMENTAL APPARATUS-The polarograph used in this work was the Cambridge instrument, the micro-amps.per relationship between galvanometer deflection and current being 5.3 xApril, 19471 DETERMINATION OF TIN, LEAD, AND ZINC IN PHENOL 151 division. All the polarograph work was done in a room with the temperature 20" C. f 1.0" C. Hydrogen was used for de-oxygenating the solutions by bubbling the gas through for 5 minutes. A mercury anode was used for tin and lead in acid solution, and a saturated calomel anode for lead and zinc in alkaline solution. The capillary constant was m2/3 t1Is = 2.09 mg2l3 sec.-& at -0.45 volt in 10 per cent. hydrochloric acid (wlw), 1-88 mg2I3 sec.-& at -0.75 volt in 0.5 X sodium hydroxide, and 1-80 mg.2/3 sec.-t at -1.5 volt in 0.5 N sodium hydroxide. The step height was taken as the vertical height in divisions between the points of intersection obtained by drawing straight lines through the photographic trace before, through and in line with, and after the step. DETAIL OF EXPERIMENTAL WORK- Much time was spent in unsuccessful attempts to find a base solution in which all three metals could be determined polarographically and, after trials of various solutions, we decided upon an acid "base" solution for the tin, and an alkaline "base" solution for the lead and zinc after removal of the tin with hydrobromic acid and bromine.As extraction is much quicker than ashing we dissolved the sample in benzene, extracted with dilute hydro- chloric acid and determined the amount of the metals in the extracts. Three extractions were sufficient to remove the whole of the metallic constituents. This was proved on samples of phenol containing known amounts of tin, zinc, and lead.Pure phenol (m.p. 40.4" C.) was distilled twice in all-glass apparatus; the final material showed no trace whatever of any of the three metals when examined by the method given above. Tin was introduced by boiling a known weight of tin foil in a weighed quantity of phenol for three hours, after which the tin foil was removed, carefully washed with benzene and methanol, dried and reweighed. It was thus ascertained that tin equivalent to 20 parts per million had dissolved in the phenol. By the method of analysis described above, duplicate tests indicated 18 and 19 parts of tin per million, a result of adequate accuracy. Similarly, a solution of lead in phenol was prepared by boiling redistilled phenol with a known weight of bright sheet lead in exactly the same manner as with tin.This gave a figure of 30 parts per million based on loss of weight, and a polarographically determined figure of 31 parts per million. A solution of zinc in phenol was prepared by boiling the redistilled phenol with a weighed amount of zinc dust, allowing the excess of zinc to settle out from the hot phenol, pouring off into a beaker as much phenol as possible, then recovering the zinc dust on a Gooch filter crucible, washing with methanol and finally drying at 105" C. This showed that the phenol had dissolved zinc equivalent to 75 parts per million. Analysis by the polarographic method given above showed 71 parts per million.As the zinc dust contained some zinc oxide the results are in good agreement, and as the phenol to be examined seldom contains more than 8 parts per million the accuracy ig quite adequate. It was found that small amounts of phenol had an effect on the step height of tin in 10 per cent. hydrochloric acid solution but had little, if any, effect on the step height of lead in the same acid solution. In the extraction of the phenol in benzene solution with 10 per cent. hydrochloric acid under the conditions of the analysis, approximately 0.020 g. of phenol was found in the final extract, and this amount of phenol must be added in the preparation of standards for tin. Since the lead and zinc are determined after evaporation to dryness and treatment with hydrobromic acid and bromine, phenol is absent from the solution polaro- graphed for these metals.In acid solution, tin and lead are reduced at the same half-wave potential of -0.45 volt against a mercury anode; therefore, in order to determine the lead, the tin must be separated from the lead either by using another base solution in which the two waves areseparated and can be measured, or by removing the tin chemically. The latter method was used, as it was found extremely difficult to separate the two waves sufficiently for accurate measurement. By means of hydrobromic acid and bromine, tin (06mg. in 25ml. of the hydrochloric acid extract, = 20 p.p.m. in the phenol) was completely removed in two treatments. Generally, one treatment was sufficient, but occasionally a trace of tin was left; hence we have prescribed two treatments in the final method.After Iemoval of tin, the lead and zinc were extracted from the residue with N sodium hydroxide; three extractions are necessary to remove completely the whole of these metals; and the final solution is made 0.5 N before polarographing. The extraction of the metals from the phenol was next investigated.152 OFFICIAL APPOINTMENTS [Vol. 72 We realise that they depend on the dimensions of the capillary used, etc., but include them as a guide to other workers. At a sensitivity of 1/10, we found that the following relationships hold. Tin in 10 per cent. HCl by weight, containing 0.02 g. of phenol per 25ml.- Lead in 10 per cent. HC1 by weight, containing 0.02 g. of phenol per 25 m1.- Lead in 0.5 N sodium hydroxide solution- Zinc in 0.5 N sodium hydroxide solution- 1 division of step height = 0.029 mg.of tin per 25 ml. 1 division of step height = 0.0415 mg. of lead per 25 ml. 1 division of step height = 0.0415 mg. of lead per 25 ml. 1 division of step height = 0.015 mg. of zinc per 25 ml. ACCURACY OF METHOD- .To establish the accuracy of the method, mixtures were made up from doubly distilled phenol and the solutions of the three metals already described, so as to contain known amounts of the metals, in about the same quantities as the samples under examination-tin about 10 parts per million, zinc less than 5 parts per million, and lead less than 1 part per million. Results are shown in the Table below. TABLE Present, parts per miNion Found, parts per million Tin e z i l ; c Lead 21 nil 11 1 20 nil 10 2 15 5 15 14.5 4 14 3 10 10 20 11 9 21 4 5 15 nil 5 14 nil 5 10 5 15 11 4 14 Mixture Tin -c Lead The method is thus entirely adequate for this type of analysis, and compares well with any other method for traces of such metals in material of this type. SUMMARY- Traces of tin, lead, and zinc in phenol may be conveniently determined by the polaro- graph. Twenty-five g. of the phenol are dissolved in benzene and the solution is extracted with dilute hydrochloric acid. Aliquots are taken for the polarographic determination of the three metals, tin in acid solution, and lead and zinc in alkaline solution after removal of tin with hydrobromic acid and bromine. The three determinations can be completed in less than three hours. REFEREKES 1. 2. 3. 4. Muller, 0. H., “The Polarographic Method of Analysis,” published by The Journal of Chemical Kolthoff, I. M,, and Lingane, J. J., “Polarography,” 1941, pp. 263, 267, 271. Cholik, J., Rubbard, D. M., and Burkey, K. E., Ind. Eng. Chem., Anal. Ed., 1943, 15, 754-759. Levine, L., J . Industrial Hygiene and Toxicology, 1945, 27, 171-177. Education, Easton, Pa., U S A . IMPERIAL CHEMICAL INDUSTRIES LIMITED BILLINGHAM DIVISION RESEARCH DEPARTMENT

ISSN:0003-2654    

DOI:10.1039/AN9477200149

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction 152 OFFICIAL APPOINTMENTS [Vol.72 Official Appointments PUBLIC ANALYST APPOINTMENTS NOTIFICATION of the following appointments of Public Analysts has been received from the Ministry of Health since the last record in THE ANALYST (1947, 72, 64). Public Analysts Appointments COOMBES, A. H. (Deputy) . . .. . . City of Birmingham. HAWKINS, Ernest Stephen . . .. . . County Borough of Canterbury. WORDSWORTH, C. H. . . . . .. . . Borough of Luton. The Urban District of Solihull has been constituted a, Food and Drugs Area, and the U.D. Council propose to appoint Mr. F. G. D. Chalmers as their Public Analyst.April, 19471 MINISTRY OF HEALTH 153 OFFICIAL AGRICULTURAL ANALYST APPOINTMENTS NOTIFICATION of the following appointments of Official Agricultural Analysts has been received from the Ministry of Agriculture and Fisheries since the last record in THE ANALYST (1946, 71, 586). Ojicial Agricultural Analysts Appointments FLINT, John Walter (Deputy) . . .. .. . . Administrative County of Kent. HAWKINS, Ernest Stephen . . .. .. . . County Borough of Canterbury. WHITTLE, Ernest George .. .. .. . . County Borough of Bristol.

ISSN:0003-2654    

DOI:10.1039/AN9477200152

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction April, 19471 MINISTRY OF HEALTH 153 Ministry of Health STATUTORY RULES AND ORDERS” 1947 No.612. The Ice Cream (Heat Treatment, etc.) Regulations. Dated April 2, 1947; Price Id. These vegulutions come into opevation on thefirst day of May, 1947, with the exception of 3 (b) ( i v ) , which becowes operative on a date to be fixed later. In these regulations-“ice-cream” includes water ices and any article, under whatever descrip- tion it is sold, which is so similar to ice-cream as to constitute a substitute therefor: “ingredients” includes sugar and dried egg, but does not include colouring or flavouring materials or fruit, nuts, chocolate, and other similar substances; and “complete cold mix” means a product which is capable of manufacture into ice-cream with the addition of water only, is sent out by the manufacturer in airtight containers, and has been made by evaporating a liquid mixture which has already been submitted to heat treatment comparable with that prescribed in these regulations.3. The following requirements shall be observed in the manufacture of ice-cream intended for sale for human consumption : ( a ) Where a complete cold mix is used which is reconstituted with wholesome drinking water and to which nothing is added other than colouring or flavouring materials, fruit, made by the Minister of Health under the Food and Drugs Act, 1938. 1. 2. ~ _ _ _ _ _ _ _ ~ ~ ~ ~ ~ ~~~ ~~~~~ ~~ * Obtainable from H.M.Stationery Office. Italics signify changed wording.154 MINISTRY OF HEALTH [Vol. 72 nuts, chocolate, or other similar substances, the reconstituted product shall be con- verted into ice-cream within one hour of reconstitution. In any other case, after the ingredients have been mixed together, the following pro- visions shall apply :- (i) the mixture shall not be kept for more than one hour a t any temperature which exceeds 45" F. before being subjected to heat treatment in accordance with the next following sub-paragraph ; (b) (ii) the mixture shall be subjected to heat treatment as follows:- It shall be raised to and kept a t a temperature of not less than 150" F. for (iii) after the mixture has been subjected to heat treatment as aforesaid it shall be reduced to a temperature of not more than 45" F.within 1+ hours and shall be kept a t such a temperature until the freezing process is begun; (iv), (v), and (vi) the local authority i s given power to specify the necessary indicating and recording thermometers arid to exercise supervision over all apparatus. A n y temperature charts shall be kept for at least a month. 30 minutes or alternatively of not less than 160" F. for 10 minutes; 4. Ice-cream shall not be sold or offered for sale unless either- ( a ) it has been kept a t a temperature not exceeding 28" F. sinceSt was frozen, or (b) if its temperature has risen above 28" F. a t any time since it was frozen, it has again been subjected to the treatment prescribed by sub-paragraphs (i), (ii), and (iii) of regulation 3 (b) and, after having again been frozen, has been kept a t a temperature not exceeding 28' F.6. lce-cream shall be protected from dirt, dust or other contamination a t all times during its manufacture, storage and distribution, and all apparatus and utensils brought into contact with ice-cream during its manufacture, storage or distribution shall be thoroughly cleansed imme- diately after use and shall be kept clean a t all times. CIRCULAR 69/47 This circular explaining the above regulations was issued on the 10th April, 1947, by the Ministry of Health. It states that the regulations jteferred to in Circular 183/46, ANALYST, 1946, 71, 539, have now been made (see above) and come into force, with the exception of those Yelating to thermometers, on the 1st of May, 1947.They define the conditions under which the ingredients of ice-cream shall be heat treated, cooled, fyozen, and stored pvevious to sale. An exception i s made for "complete cold mix" requiring the addition of no ingredied other than water, f o r which heat treatment i s not required, but which must be frozen within an hour of its being reconstituted. Provided that all practicable steps have been taken to procure the necessary apparatus, f a i l w e to obtain it before the 1st 0-f M a y , 1948, i s held to be a defence to a charge of non-compliance with regulation 3 (b) (iii). The date from which the indicating and recording thermonzeters considered necessary by local authorities are to be put into compulsory use remains to be announced by the Minister; but the charts of any recording instruments i n use are to be kept f o r at least a month, even though the compulsory requirement of such thermometers has not come into operatibn.The general cleanliness of all materials and apparatus, together with the operation of the plant, i s subject to supervision by the local authority. The Minister has given further consideration to the prescription in the Regulations of a bacteriological standard of cleanliness for ice-cream, but he is still not satisfied that there is any test, the reliability of which is sufficiently established to justify its use as a statutory test, non-compliance with which would constitute an offence. He d'esires, however, to draw attention to a form of methylene blue test, adapted for testing ice-cream, particulars of which have been published in the Ministry of Health's Monthly Bulletin for March, 1947. The Bulletin is sent to Medical Officers of Health. Application for these particulars by other persons interested should be made to the Secretary, Ministry of Health, Whitehall, S.W.l. As pointed out in the Bulletin, the conclusions and suggested grading are at present provisional, but the Minister is advised that this test of bacterial cleanliness appears to provide the best available for the present purpose. It is suggested that if, out of the four grades recommended, ice-cream consistently fails to reach grades one and two, it would be reasonable to regard this as indicating defects of manufacture or of handling which call for further investigation. The Minister has also had regard to the representations which have been made to him on a number of other points with a view to strengthening the Regulations, particularly in relation to the pro- tection of ice-cream after manufacture. While, however, he fully appreciates the importance of the latter, he has come to the conclusion that the Regulations as now made represent as much as it is a t present practicable to require. At the same time i t is simple and cheap to perform. April 10, 1947

ISSN:0003-2654    

DOI:10.1039/AN947720153b

出版商:RSC    

年代:1947

数据来源: RSC