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

ISSN:0003-2654    

DOI:10.1039/AN938630775b

出版商:RSC    

年代:1938

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-ction

ISSN:0003-2654    

DOI:10.1039/AN9386300777

出版商:RSC    

年代:1938

数据来源: RSC

摘要:

7 82 BARRITT BOWEN GOODALL AND WHITEHEAD: The Determination of Acid in Wool BY J. BARRITT B.Sc. A.R.C.S. A.I.C. H. H. BOWEN, F. L. GOODALL M.Sc. -4s~ A. WHITEHEAD (Read at the Meeting Xovember 2nd 1938) THE importance of simple and accurate methods for the determination of acid in wool may be realised from the attention the subject has received and the large amount of investigation applied to it. Despite this however the work so far carried out has not resulted in establishing any one method as absolutely reliable or as more reliable than others. Many of the earlier methods relied upon the neutralisation of the acid present in the material by an excess of a weak alkali-the excess of alkali being determined. Such methods are inaccurate since the wool readily absorbs alkali and the amount absorbed and therefore the accuracy of the acid determination will depend upon the nature and the amount of the excess of alkali used.One of the earliest methods of determining acid in wool was to add an excess of ammonia but this procedure has been criticised by Lloyd1 owing to the ab-sorption of ammonia by wool and the uncertainty of any blank made to allow for such absorption. Similarly Barritt2 has criticised the triethanolamine method of Trotman and Gee,3 though the absorption of the base in this method is much less serious than in the ammonia method. The sodium bicarbonate extraction method of Meunier and Rey4 is a similar method and suffers from the same inherent defect. Hirst and King5 modified a suggested method of Woodmansey6 for the deter-mination of sulphuric acid in wool.They digested the acid material with an aqueous suspension of magnesium carbonate and determined the soluble sulphat e in the extract as barium sulphate. This method is limited to the determination of sulphuric acid and further any sodium or calcium sulphate present would be returned as sulphuric acid. Calcium carbonate is also used in a method due to Trotman and Gee and the carbon dioxide liberated by the acid is expelled by boiling and absorbed in baryta. The method was found to give values similar to those obtained with the sodium acetate sodium bicarbonate or triethanolamine method provided the time of distillation was not too long. In our opinion the methods mentioned above suffer from obvious defects or are too lengthy in operation to merit detailed study in an exploration for a reliable and rapid method for the determination of acid in wool and accordingly attention was directed to three methods which have been subjected to less criticism than those already mentioned.It is of interest to note that when the work was started each of the three methods was in routine use in the laboratories of at least two of the present authors. These methods are:-(&) The sodium terephthalate method of Hirst and King5; (b) the sodium acetate distillation method of Trotman and Gee3; (c) the pyridine method of Barritt.2 All three methods are claimed to give satisfactory recovery of any acid present. It appeared desirable however to determine whether or not the method THE DETERMINATION OF ACID IN WOOL 783 gave comparable results and if not which method could be considered the most reliable in respect both of absolute accuracy and of reproducibility in the hands of different operators.Comparative tests were therefore undertaken and except where otherwise stated the tests described were carried out independently in the separate laboratories controlled by the present authors. The essential features of the respective methods are described below. fa) THE SODIUM TEREPHTHALATE METHOD.-A definite volume of a standard sodium terephthalate solution (0.1 N ) is added to the sample (e.g. 2 g.) which has been thoroughly wet out in distilled water. The sample and liquor are heated to 60" C. and allowed to stand for two or three hours. An aliquot portion of the liquor is withdrawn and an excess of standard sulphuric acid (0.1 N ) is added to it.The precipitated terephthalic acid is filtered off and the excess of sulphuric acid in the solution is determined by titration with sodium hydroxide solution (0.1 N ) , bromophenol blue being used as indicator, For certain dyed materials which show a tendency to bleed the determination may be carried out in the cold the steeping being allowed to proceed overnight. (b) THE SODIUM ACETATE DISTILLATION METHOD.-(1) Mineral Acid.-The sample is wet out in a little distilled water in a 500-ml. distilling flask and 0.5 to 1 g. of sodium acetate is added. The sample and sodium acetate solution are steam-distilled and about 650 ml. of distillate are collected. The distillate is titrated with 0.1 N sodium hydroxide solution phenolphtha-lein being used as indicator.Stress is laid on the importance of making the water in the steam generator alkaline so that no carbon dioxide is collected in the distillate. A blank determination without the sample is made in the apparatus. (ii) Organic Acids (e.g. acetic or formic acid).-For such acids it is only necessary to steam-distil the samples without adding sodium acetate. The usual blank determination is made. (c) THE PYRIDINE METHOD.-The sample of wool (e.g. 2 g.) containing acid is wet out by shaking in 190 ml. of distilled water and 10 ml. of a 10 per cent. solution of pyridine are added so that the final pyridine concentration is approximately 0-5 per cent. The contents of the flask are well shaken and allowed to stand for at least one hour.Suitable aliquot portions are withdrawn and the extracted acid is determined by titration with 0.1 A' sodium hydroxide solution (free from carbon dioxide) phenolphthalein being used as indicator. Of the three methods that using sodium terephthalate differs from the other two inasmuch as its results are obtained by back-titration. The sodium acetate method appears to offer a marked advantage over the other two methods in that since it is a distillation method the actual determina-tions are carried out in a colourless liquor and no interference takes place from any dyes present in the pattern under examination. One disadvantage of the method is that it requires rather bulky apparatus whereas the other two methods require only the usual volumetric apparatus.The pyridine method as originally recommended is unquestionably the simplest in operation but its accuracy has been criticised by Eavenson and Creely,' who report that the recovery of acid present is considerably reduced by any drying process to which the wool has been subjected after contact with th 7 84 BARRITT BOWEN GOODALL AND WHITEHEAD : acid. These authors recommend the use of higher temperatures in the neigh-bourhood of 100" C . for the aqueous pyridine treatment of the pattern under test. Both of these points will be discussed later. At the outset of the investigation one of us (H.H.B.) had already completed comparative tests of the sodium acetate distillation and sodium terephthalate methods on a variety of wool patterns containing respectively acetic formic and sulphuric acids and obtained markedly different acid values by the two methods.The value obtained by sodium acetate distillation was invariably much higher than that given by the sodium terephthalate method the ratio of the former to the latter varying from 1.45 to as much as 2.3. As a preliminary the remaining three of us carried out comparative tests by preparing their own acid wool by treatment of commercially scoured woollen materials of unknown alkali-content with a known quantity of sulphuric acid (about 4 per cent.) and determining the amount of acid recovered from the cloth by the three methods. Table I gives the respective results expressed as a per-centage of the acid added of which some has been used up in neutralisation of the alkali in the wool and some Method Sodium terephthalate Sodium acetate .. Pyridine left in the treatment liquor. TABLE I Recovery of added acid Per Cent. Per Cent. Per Cent. 53.8 47.0 55.0 54.8 45.9 -- 48.5 -62.5* 51.0 73.0 59*8* 52.3 71.0 60*0* 49.2 67.3 67.3 56.0 66.9 67.3 56.0 57.4 64.3 - 53.6 64.3 I-A \ J.B. F.L.G. A.W. Comparison of the above results shows that the sodium terephthalate method invariably gives results rather lower than those given by the other two methods, but the difference between the sodium terephthalate method and sodium acetate distillation method was not so pronounced as in the results previously obtained by one of us (H.H.B.). Since general considerations would suggest that the pyridine method could not possibly return more acid than is actually present (the only effective criticism of the pyridine method so far put forward is that it f a d s to give complete recovery of acid) it was felt that further work on the sodium terephthalate method should not be pursued unless serious defects were found in either or both of the other methods.It may be remarked that already at this stage we had found substantial variation in the blank values which are integral parts of the sodium acetate distillation method. For example the values marked by an asterisk in the above table were the results of deducting from the observed acid values an average blank value of 0.56 per cent. derived from the five blank figures 0-77, 0.67 0-23 0.25 and 0.89 per cent.Obviously such variation may be very serious THE DETERMINATION OF ACID I N WOOL 78.5 It was now decided that comparative independent trials should be made, on one and the same sample of acid wool using materials treated respectively with sulphuric acid formic acid and acetic acid these acids being chosen as those most commonly used in commercial treatment of wool. The measurements were made by the pyridine method only using a period of one hour’s steeping in the pyridine liquor as originally recommended and also with steeping over-night. Adequate quantities of commercially scoured cloth were treated by one of us (F.L.G.) for one hour at boiling temperature with the amounts of acid shown in Table 11. The quantities of acid found by the individual authors in the material and in a commercially dyed green material of unknown acid-content are reported in Table I1 as the mean of two or more determinations in each instance.TABLE I1 J.B. * One Over-hour night Treatment Per Per Cent. Cent. Sulphuric acid 3-93 per cent. 2.20 2.36 Formic acid 4.53 per cent. . . 0.46 0.52 Acetic acid 1.58 per cent. . . 0.13 0.18 Green cloth . . . . 1-90 1.96 H.H.B. r-+ One Over-hour night Per Per Cent. Cent. 2.26 2.58 0.64 0.81 - 0.35 1.90 2.10 F.L.G. r-J-7 One Over-hour night Per Per Cent. Cent. 2.08 2.16 0.76 0.14 0.14 0.17 1.83 1-90 A.W. * One Over-hour night Per Per Cent. Cent. 2.60 3.06 1.15 1.15 0.60 0.75 2-08 2-20 I t will be seen that although each investigator was using samples taken from the same laboratory-treated patterns very divergent results were obtained, particularly with the two organic acids.On the other hand this divergence was much less evident with the commercially-dyed green cloth with which reasonably concordant results were obtained in all four laboratories. Since two of us (H.H.B. and F.L.G.) had already obtained very concordant results with the pyridine method on a large number of commercial samples (to be described in full later) it was considered that the discrepancy in values found on the laboratory material might have arisen from a non-uniform distribution of acid in the cloth caused probably by the difficulty of drying evenly a large piece of cloth under laboratory conditions. On this view the better agreement in the results for the commercial pattern could be attributed to the probability that this diffi-culty of drying and consequent uniform acid distribution did not arise with the commercial cloth dried in the ,full open width on a tentering machine.In order to check this point it was decided to repeat the tests on fresh material, treated in the laboratory with the various acids by one of us (F.L.G.) conditioned, accurately sampled and weighed into 2-g. samples and distributed by another of us (J.B.). The conditioning sampling and weighing were carried out as follows :-The piece of acidified cloth was allowed to condition for several days in a room main-tained at 70 per cent. relative humidity and all weighings of the samples were made in this room.A strip about one inch in width was first removed from the edges of the cloth and the residual material was divided into sixteen equal areas. Each of these smaller areas was divided into small approximately equal portions th 786 BARRITT BOWEN GOODALL AND WHITEHEAD : number of portions being arranged so that sixteen of them weighed approxi-mately 2 g. The samples used in the determination of acid (2 g.) were obtained by taking one small portion of cloth from each of the sixteen zones their combined weight being adjusted to 2 g. either by trimming the portions or by adding fragments derived from the various zons. The average values found are given in the table below. TABLE I11 J.B. H.H.B. F.L.G. -- One Over- One Over- One Over-hour night hour night hour night Treatment Per Per Per Per Per Per Cent.Cent. Cent. Cent. Cent. Cent. Sulphuric acid 3-79 per cent. 2.25(3) 2-32(3) 2.06(1) 2.36(1) 2.24(3) 2.37(2) Formic acid 4.64percent. . . 0.55(3) 0.60(3) 0-53(1) 0.59(1) 0-57(3) 0-61(2) Acetic acid 2-57 per cent. . . 0*15(3) 0.20(3) 0-17(1) 0*19(1) 0-19(3) 0.23(2) (The figures in brackets refer to the number of determinations made.) One hour Per Cent. 2*32(6) 0-53(3) 0- 1 7 (6) Table I11 shows clearly that the precautions taken with regard to sampling and conditioning had resulted in much better agreement between the four laboratories. In our opinion the figures showed the pyridine method to be reliable from the point of view of reproducibility and this view was confirmed by the results obtained independently on a number of commercial cloths as given in detail in Table IV.Certain of the samples were not available to two of us (H.H.B. and A.W.). The acid in the sample is calculated as sulphuric acid. TABLE IV Sample J.B. H.H.B. F.L.G. A.W. marked Per Cent. Per Cent. Per Cent. Per Cent. A2 A4 A5 B12 B13 B14 B25 €326 0.10 0.33 0-26 2.32 2-26 2.15 2.65 2.16 - 0.20 -- 0.42 -- 0.35 -2.30 2.3’7 2.31 2.35 2.32 -2.25 2-23 2.20 2-80 2.68 2-70 2.25 2-2 1 2.31 The close concordance shown by these figures indicated definitely that the pyridine method in the hands of several operators could give reproducible results and the experiments as a whole indicated that accurate sampling and conditioning of laboratory prepared samples is of great importance in investigating the acid-content.No evidence had as yet been produced however to show that the pyridine method would return all the acid actually present in the material and at this stage it was decided to make comparative trials of the pyridine and sodium acetate distillation methods since the latter had given rather higher values in general in the work summarised in Table I. The scheme first adopted was as follows :-Adequate quantities of undyed material were made slightly acid with sulphuric formic and acetic acids respec-tively the cloths being treated at boiling temperature with sufficient quantitie THE DETERMINATION OF ACID I N WOOL 187 of the acids to produce an acid reaction when a sample so treated was digested with 25 times its weight of distilled water for 30 minutes at 40” C.The “acid reaction” obtained corresponded to a decrease of 0.3 to 0.5 in the pH of the incubated extract as compared with the pH of the original distilled water similarly treated. The slightly acid cloths so prepared were conditioned sampled and weighed in 2-g. portions as previously described. The acid-content of the samples as received was then determined in each laboratory by both the pyridine and the sodium acetate distillation methods. For each method of determination 2-g. samples of each of the acid cloths were then treated separately in a 40 1 liquor ratio for 1 hour at boiling temperature with a further 2.5 per cent. of the acid originally present in the samples. For the two organic acids this treatment took place under a reflux condenser.The total acid in both cloth and liquor was then determined together. By this method of test it was hoped to be able to determine whether or not the two methods investigated would return all the additional acid introduced. Most of us had already found the sodium acetate distillation method to be subject to variation in blank values and in actual values which it was thought might be due to variation in the rate of distillation and in the volume of liquor present in the distilling flask. In addition some of us had frequently obtained low results by this method and it was therefore arranged to continue distillation until much more than the 650 ml. of distillate specified by the original authors of the method were collected the times required to obtain any particular volume of distillate and the average volume of liquid present in the distilling flask throughout the distillation being noted.The results obtained for the distillation method are given in Table V. TABLE V Total acid found -7 Volume of Time of (a) before (b) after distillate distillation addition addition Per Cent. Per Cent. J.B. Sulphuric acid cloth; 2.45 per cent. of added acid 1. 650 ml. 37 mins. 1-12 3.15 2. 650 , 38 , 1.10 3.12 3. 780 , 40 1.10 3-24 1. 650 ml. 38 mins. 0.21 2.37 2. 650 , 35 , 0.18 2.18 Acetic acid cloth ; 2.5 per cent. of added acid Formic acid cloth ; 2.5 per cent. of added acid 1. 650 ml. 37 mins. 2. 650 , 35 ,, Average volume Sulphuric acid cloth ; 2.5 per cent. of H.H.B.1. 710 ml. 60 mins. 2. 730 , 60 ,, 3. 780 I 1 60 ,, 1950 , 150 ,, 0.11 2.40 0.11 2.37 Difference Per Cent. 2-03 2.02 2.14 2.16 2-00 2.29 2.26 in distilling flask 100 ml. added acid 0.76 2.7 1.94 0-76 2.7 1.94 0.76 2.7 1.94 1.52 3.63 2-11 Recovery Per Cent. 83 82 87 86 80 92 90 78 78 78 8 BARRITT BOWEN GOODALL AND WHITEHEAD : TABLE V-contiwed Total acid found 7 T-olume of Time of ( a ) before (6) after distillate distillation addition addition Difference Per Cent. Per Cent. Per Cent. H.H.B. Formic acid cloth 2.5 per cent. of added acid 1. 780 ml. 60 mins. 0.53 2.55 2-02 2. 790 I I 60 * 0.53 2.58 2.05 3. 790 J J 60 , 0.53 2.55 2.02 2040 ) 150 1 1.10 3.34 2-24 Acetic acid ~20th 2.5 per cent.of added acid 1. 730 ml. 60 mins. 0.54 2-13 1.59 2. 730 ,I 6o J f 0.54 2.37 1.83 3. 700 J 1 60 1 . 0.54 2.25 1.71 1930 , 150 1 9 1.11 3-3 2.19 Average volume in distilling flask 200 to 260 ml. F.L.G. Sulphuric acid cloth ; 2.45 per cent. of added acid 1. 660 ml. 50 mins. 0.54 2-03 1.49 2. 660 > J 55 * I 0.54 2-40 1-86 1020 I ) 85 J 0.74 2-77 2-03 3. 660 J J 45 J ? 0.54 1.86 1-32 1310 , 95 > J 0.88 2.65 1-77 4. 700 I t 45 J I 0-54 1.78 1.24 1350 , 95 I 0.88 2-65 1.77 Formic acid cloth; 3.11 per cent. of added acid 1. 690 ml. 50 mins. 0-33 2.30 1.97 1050 ,) 80 , 0.42 2.83 2.41 2. 660 , 50 ? t 0.33 2.25 1.92 1210 ,) 95 I I 0-45 2.06 2.61 1820 , 135 I J 0.59 3.52 2.93 Acetic acid cloth 2.52 per cent. of added acid 1. 610 nil.50 mins. 0.41 1-64 1.23 1250 ,? loo > J 0.69 2-36 1.67 1870 I 145 J I 0.93 2-91 1.98 2. 700 , 50 I 0.41 1.87 1-46 1350 loo J J 0.69 2.53 1.84 1940 I 145 >> 0.93 2.92 1.99 Average volume in distilling flask 250 to 300 ml. A.W. Sulphuric acid cloth ; 2.5 pev cent. of added acid 1. 600 ml. 90 mins. 0.72 3.01 2.29 2. 600 I 105 , 0.74 3-08 2.34 Fovvnic acid cloth ; 2.5 per cent. of added acid 1. 600 ml. 105 mins. 0.46 2.69 2.23 2. 600 11 > J 0.46 2.67 2.21 Acetic acid cEoth 2.5 per cent. of added acid 1. 600 ml. 90 mins. 0.60 3.15 2-55 2. 600 ,¶ 90 I ) 0.60 3-18 2.58 Average volume in distilling flask 200 to 225 ml. Recovery Per Cent. 81 82 81 90 64 73 68 88 61 76 83 54 72 51 72 63 77 62 84 92 49 66 78 57 72 79 91 93 89 88 102 10 THE DETERMINATION OF ACID I N WOOL 7 8C It is noteworthy that only one of us (A.W.) obtained recovery values of a reasonably high standard whilst the values obtained by two of us (H.H.B.and F.L.G.) are very low indeed even when distillation was prolonged until the distillate was three times as large as the 660 ml. originally specified. It may be remarked that in the latter tests the blank experiments were also continued for a correspond-ingly increased time. Pronounced variations were also found in acid values ob-tained by each of us in tests on identical material i.e. on the acidified cloths before treatment with any additional acid. No explanation of the variable nature of the results can be found in consideration of time or rate of distillation or volume of liquor in the distillation flask but the variation is so large as to make it clear that the method is unreliable and cannot be recommended for general use.It may be added that one of us (F.L.G.) obtained positive values by the method for acid-content on a material known to be definitely alkaline. The pyridine method gave more promising results throughout as the values shown in Table VI indicate. TABLE VI J .B. H.H.B. F.L.G. A.W. Acid added Acid added Acid added Acid added: 2-45 per cent. 2.5 per cent. 2.45 per cent. 2.5 per cent. Sudphwic acid fiatteyns- Per Cent. Per Cent. Per Cent. Per Cent. Original acid content . . 0.56 , 9 > 0.61 5 0 . 5 7 > > J 2 0.54 J 0.54 00::; } 0.645 0.69 After treatment .. 2-98} 2.94 1 ,?:I?} Acid recovered 2.39 2.41 9.365 2.32 Recovery 97.5 96.4 96.5 92.8 I > > 2.96 2-96 2.98 2.95 2.99 3-01 3.01 ,* , 2.96 2.94 Formic acid patteyns-Original acid content . . , * I 3 > Y > ? After treatment . . 2 I , ,f Acid recovered Recovery Acid added: 2.5 per cent. Per Cent. 0-2 1 2.85 2.75 2.57 102.6 Acid added: 2.5 per cent. Per Cent. 0.18 3-67 2.71 ] 2.70 2-7 1 8-52 100.8 Acid added : 3.11 per cent. Acid added : 2.5 per cent. Per Cent. Per Cent. 0.28 0.30 0-29 } Oe30 2-78 3.1 6 2.50 3.38 101.6 100.0 -acid added Acid added Acid added Acid added: 2.5 per cent. 2.5 per cent. 2-52 per cent. 2.5 per cent. 0.07 Acetic acid patterns- Per Cent. Per Cent.Per Cent. Per Cent. Original acid content . . > f ) I 1 9 Y J 0.08 J -3.56 2-43 4-41 9 6 4 -After treatment . . 2.55 2.59 2.48 2.46 2.62 2.50 ] 2.51 i:: ) 2.50 2.68 Acid recovered 2.43 3-44 Recovery 97.2 97-6 96. 790 BARRITT BOWEN GOODALL AND WHITEHEAD : With one exception recovery values of 96 per cent. or over were obtained throughout by the pyridine method and in addition attention may be drawn to the concordant results obtained by each laboratory in determining the original acid-content of the materials sampled. Besides giving a satisfactory reproducibility in the hands of different operators, the pyridine method was thus shown to be capable of returning all the additimal acid introduced but further investigation was required on several points in con-nection with the method before it could be regarded as thoroughly reliable.These were : A possible zero error in the method-Since most of our experimental results by the pyridine method were higher than corresponding results by the distillation method this possible error did not appear likely to be very large but it was considered worthy of investigation. The efect of drying after contact with acid.-Mention has already been made of the criticism of Eavenson and Creely' that the amount of acid recovered is materially reduced according to the conditions of drying the material after contact with the acid. This led them to recommend extraction with pyridine at temperatures approaching boiling-point but this recommendation would in our opinion lead to difficulties with some dyed materials for a third reason vix.: (c) Coloration.-This is due to the bleeding of dye into the pyridine solution where coloured materials are being examined.(a) A possible zero error in the method-Any investigation of this question required a supply of wool of a satisfactory degree of purity. This was only available to two of us and as the method of investigation differed in both instances, each is given in full here. One of us (J.B.) treated raw 64's Cape wool in three changes of warm benzene, followed by air drying and removal of foreign matter by opening out the locks. The sample was extracted in a Soxhlet apparatus with alcohol and then washed for some days in distilled water the water being changed two or three times daily.The wool was finally dried in the air and conditioned at 70 per cent. R.H. It had an ash-content of 0.55 per cent. and a 1 50 extract with distilled water showed a fiH of 6.4. Samples of this wool were refluxed with 3 per cent. sulphuric acid for 1 hour, and the acid-content in wool and liquor were determined together by the original method (1 hour's steeping). In three successive experiments the acid-content amounted to 2.86 2.92 and 2.85 per cent. equivalent to an average recovery of 9 4 3 per cent. A similar set of three experiments in which the acid in the wool and the liquor was determined separately gave the following results : (a) (6) -4cid in wool per cent. . * 2.19 2-17 2-03 Acid in liquor per cent. . . 0.68 0-72 0.82 Total acid per cent.. . . . 2.87 2.89 2-85 Another of us (F.L.G.) used commercially scoured yarn which was purified Forty g. of yarn were treated for 30 minutes at 80" C. in 500 ml. of water The yarn was washed off in distilled by the following method: containing 6 ml. of conc. hydrochloric acid THE DETERMINATION OF ACID I N WOOL 791 water and extracted in a Soxhlet extractor with distilled water for 2 hours after which the ash-content was determined. If the ash-content was above 0.05 per cent. the above procedure was repeated but this repetition was not usually necessary. The yarn was then immersed in 500 ml. of water containing 20 ml. of pyridine, heated to 60" C. and allowed to stand overnight after which it was washed off with distilled water and extracted for 3 hours in a Soxhlet apparatus with a mixture of 50 ml.of water 60 ml. of methylated spirits and 2 to 5 ml. of pyridine. The yarn was dried and extracted with methylated ether in a Soxhlet apparatus for 3 hours. The result of this treatment is a wool which has an ash-content less than 0.05 per cent. and acid-content (by the pyridine method) less than 0.1 per cent., and shows PH 5.0 to 5.8 on digestion in 25 times its weight of distilled water which similarly treated alone shows a pH of the order of 5.6. The actual samples used for the determinations which follow had the following characteristics :-ash-content nil; pH 5.20 (distilled water 5.6) ; acid-content 0.06 per cent. by the standard pyridine method. Samples of this wool were treated for 45 minutes under reflux with sulphuric acid the solution was cooled and the acid in the wool and the liquor together was determined.The following figures were obtained : Acid added Acid recovered Recovery Per Cent. Per Cent. Per Cent. 1. 3 -. 3. 0.223 0.22 98.9 0441 0.4 1 92.9 0.882 0.85 96.3 The figures given under "acid recovered" are of course values obtained after deducting from the observed final values the 0.06 per cent. of acid found in the original cloth. The work of one of us (J.B.) was therefore carried out on a purified wool which deviated from an ideal standard of purity in having a very slight alkali-content, as indicated by the pH value of a water extract and its asli-content. On this wool the pyridine method gave 94 per cent. recovery of acid added to the extent of about 3 per cent.The work of another (F.L.G.) was carried out on a wool from which inorganic matter had been removed and which owing to its method of preparation was in fact slightly acid. With such wool the pyridine method gave recovery values of more than 92 per cent. with much smaller amounts of added acid. These values are sufficient to indicate that if a zero error exists at all it is of very small magnitude. (b) Efect of dvying after contact with acid.-The significant experiments made by Eavenson and Creely' refer to three 2.5-g. samples of purified yarn wetted out in warm water squeezed placed in flasks and treated respectively with 5 l O and 15 ml. of 0.1 N sulphuric acid followed by drying in a current of air at about 20" C. for 3 days after which the yarn was quite dry.The contents of the flask were then digested for 1 hour at 55" C. with 0.5 per cent. pyridine solution and the acid was determined in the usual manner; recovery values of 79.5 85-5 and 88.0 per cent. respectively were obtained. The yarn in question was purified* by scouring the greasy wool under commercial conditions with petroleum naphtha and water 792 BARRITT EQWEN GOODALL AND WHITEHEAD : followed after spinning by extraction of the yarn with carbon tetrachloride and then with alcohol. No ash determinations were made but it is probable that after the treatment described the yarn would have an ash-content of the order of 1 per cent. which might have a significant effect in reducing the amount of recoverable acid. Our own investigation of the effect of drying on the pyridine method of deter-mination was carried out in two stages in the first of which one of us (H.H.B.) was unable to take part.Commercially scoured white flannel was treated under dyeing conditions with 2.5 per cent. sulphuric acid 5 per cent. formic acid and 6 per cent. acetic acid, respectively and after this treatment the acidified samples were dried at room temperature and then conditioned and sampled as described previously. Acid determinations were made on the cloths as received and it was intended to repeat the determinations on all the cloths after subjecting them to further drying at higher temperatures and for varying periods. The amounts of organic acid present in the respective patterns were found, however to be extremely small (Table VII) and it was decided that heating experiments on these patterns would be of little value.-4ccordingly attention was confined to the patterns treated with sulphuric acid where the amount of residual acid was appreciable. TABLE VII Cloth treated with acetic acid Per Cent. J .B. 0.17 F.L.G. . . * . 0.18 *%.W. . . 0.26 Two sets of such sulphuric acid patterns shown in Table VIII were obtained. Cloth treated with formic acid Per Cent. 0.23 0.24 0.32 were available and the results TABLE VIII Sulphuric acid found J .R. F.L.G. A.W. Per Cent. Per Cent. Per Cent. 1. (a) Before heating . . . . 1.54 1-55 1.75 ( b ) After heating for 3 hours at 110" C. 1-56 1-58 1.82 2. (G) Before heating . . . . . . 2.37 2-38 2.45 (b) After heating for 3 hours a t 110" C.2-40 - 2.4,5 These figures show values obtained after a drying procedure which was common to all the three investigators. In addition each investigator made a variety of other tests ( e g . 26 hours at 90 to 100" C. 5 hours at 100" C. 5 hours a t 80" C. 2 hours at 120" C. 3 hours at 140" C.) and the recovery of acid after each of these treatments was in no instance lower than the values set out above. I t was now evident that the recovery of acid by the pyridine method was sub-stantially unaffected by considerable variation in conditions of heating and drying after the initial air drying employed in the preceding experiments THE DETERMINATION OF -4CID IN WOOL 793 There remained the possibility that the actual air drying gave rise to error.It was accordingly arranged to supply to each investigator samples of flannel made slightly acid with sulphuric acid and then conditioned sampled and weighed as previously. Each investigator should then (1) (2) (3) (4) The results obtained are given in Table IX. Determine the amount of acid present. Add a known amount of the order of 3 per cent. boil for 1 hour under a Treat as in (2) and evaporate to dryness on the water-bath before Treat as in (3) but dry for an extended period as in the first stage of our reflux condenser and determine the acid present in liquor and wool together. determining the acid present. work on this aspect of the problem. TABLE IX 1. 3. 4. 7 I. 1. 2. 3. 4. J.B. Acid added 3-00 per cent.Acid Acid found recovered Recovery Per Cent. Per Cent. Per Cent. A I \ - - Original pattern . . 0.20 Treated with acid only 3.26 3.06 102 Treated with acid and evaporated to dryness . . 3.07 3-87 95.6 H.H.B. Acid added 3.00 per cent. Acid Acid found recovered Recovery Per Cent. Per Cent. Per Cent. 0.245 - -3.18 2,935 97.8 A I \ 2.96 2-715 90.5 As (3) but dried hours a t 110" C. Original pattern for 3 . 2-92" 2.72 90.6 2.89 2.645 88.2 F.L.G. X.W. Acid added 2.72 per cent. 7 1 t Acid Acid Acid Acid found recovered .Recovery found recovered Recovery Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. &4cid added 3.00 per cent. A f L . . 0.17 - - 0.18 - -Treated with acid only 2.77 2.60 96.6 3-31 3.13 104.3 Treated with acid and evaporated to dryness 2.77 2.60 96.6 3.13 2.95 98.3 As (3) but dried for 3 hours a t 110" C. . . 2.73 2.56 94.1 3.00 2-92 94 * Heated a t 110" C. for 1 hour only. Two of us (H.H.B. and J.B.) found that some degree of charring occurred when the patterns were dried by either of the methods described above. One of us (F.L.G.) noticed slight yellowing of the edges of the flannel cuttings after heating at 110" C . but did not consider this serious. In view of these considerations and having regard to the findings of Harris Mease and R~therford,~ that concen-trated solutions of sulphuric acid at 25" C. can react "irreversibly" with wool, that is in such a manner that the acid-treated wool no longer liberates the whole of its content of SO on subsequent prolonged treatment with water or alkaline solutions we consider that the values given in Table IX indicate a very satisfactory recovery of all the available acid before and after drying 794 BARRITT BOWEN GOODALL AND WHITEHEAD (c) CoEoration ofthe Ziq.uor.-It will be seen from the results given under the previous heading that for routine determination in mill practice there is no necessity to deviate from the specification originally laid down by Barritt of treating the pattern under test with pyridine solution for 1 hour at room tem-perature.It is natural that more rapid and slightly more accurate results will be obtained by raising the temperature at which the pyridine treatment is carried out but in our opinion the use of higher temperatures is an unnecessary refinement and may involve a risk of dye bleeding into the pyridine solution.We have experienced some difficulty in the application of the method as originally put forward to certain heavily coloured acid-dyed materials. This difficulty appears to be associated chiefly with heavily acid-dyed cloths which contain relatively small amounts of acid by virtue of some treatment after dyeing which has removed some of the acid left in the dyeing process. The method as originally put forward has been found to be practicable with strongly coloured solutions where the colour of these solutions is not such as will mask the development of the pink colour of phenolphthalein at the end of the titration. With red or violet solutions satisfactory end-points have been obtained by using thymol blue instead of phenolphthalein.In our experience this indicator gives the same result as phenolphthalein but the colour-change, V ~ Z . from yellow to blue is quite different and can readily be detected in reddish or violet solutions. SuMMARY.-An examination of three of the methods in general use for the determination of acid in wool has been carried out in each of four independent laboratories. In initial experiments the sodium terephthalate method was found to give lower acid values than those obtained by either the sodium acetate or the pyridine method Since it did not appear possible that the pyridine method could return more acid than is actually present work on the sodium terephthalate method was not pursued. The results obtained by the sodium acetate distillation method were irregular and the method is influenced appreciably by a large blank correction which was found to be erratic.The results obtained by the four investigators by the pyridine method on cornmcrcially dyed and laboratory acid prepared cloth agreed well. Work was therefore directed to an examination of possible defects in the method such as (i) degree of recovery of acid present; (ii) degree of recovery of acid from wool dried at high temperatures; (iii) titration difficulties in coloured liquors. It has now been shown that the recovery of acid from wool whether dried at low or high temperatures is almost complete (of the order of 90 to 100 per cent.) under con-ditions as originally described; i.e. the sample is thoroughly wetted out in 0.5 per cent.pyridine (100 ml./l g. of wool) and allowed to stand for one hour at room temperature. The difficulty of determining the end-point of the titration in red or violet liquors with phenolphthalein as indicator may be Overcome by substituting thymol blue for phenolphthalein. Our thanks are due to members of our respective staffs for assistance in thi THE DETERMINATION OF ACID I N WOOL 795 work. following : For permission to publish the paper acknowledgment is made to the The Wool Industries Research Association (J.B.). The Bradford Dyers Association Ltd. (H.H.B.). The Geigy Colour Co. Ltd. (F.L.G.). The British Cotton & Wool Dyers Association Ltd. (-4.W.). ADDENDUM.-Since submitting the above account we have read with much interest the paper by Trotman and Bramley on “The Determination of Acidity in Knitted Woollen Goods.”1° In this paper Trotman and Bramley state (1) that the pyridine method “does not always give the whole of the acid present,” and (2) that in their opinion, “the only method applicable to both dyed and undyed goods is distillation with sodium acetate and titration of the acetic acid distilled.’’ We wish to make the followed observations on these two statements.(1) This statement in its literal interpretation is true since very small quantities of acid may be removed on repeated extraction of the acid-containing wool. This is to be expected since the acid will be distributed between the wool and the pyridine but chiefly in the latter. That these quantities are however, small may be seen from the following data obtained by carrying out the acid deter-mination in the usual way the sample being squeezed on a glass filter between the extractions.ACID XX WOOL Sample Sample Sample Sample Sample Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. I I1 I11 IV IV (overnight) First extraction . . 2.33 2.28 2.48 2.18 2.32 Second extraction . . 0.05 0.08 0.08 0.17 0.09 Third extraction . . 0.03 0.04 0.04 0-07 -The additional acid obtained in the second and third extractions in the above experiments is less than the values quoted by Trotman and Bramley which we attribute to their use of a 0.1 per cent. solution of pyridine instead of the 0.5 per cent. solution specified in the original method. When considerable quantities of acid are present in wool a low concentration of pyridine is not sufficient to extract substantially all the acid as is shown by the following values obtained by using various concentrations of pyridine on thoroughly sampled acid wool.Concentration of pyridine Acid found in cloth Per Cent. Per Cent. 0.05 1-86 0.1 2.2 1 0.5 3-53 We would remark that the results obtained by Trotman and Bramley in comparing the sodium acetate and pyridine methods appear to be erratic which may be due partly to the low concentration of pyridine used. In the absence of data as to the method employed in the purification of the wool and its acid or alkali content, it is not possible to draw definite conclusions from their results as to the reliability of either method 796 BARRITT BOWEN GOODALL AND WHITEHEAD (2) This opinion is based upon the admitted advantage that the sodium acetate distillation method gives a colourless titration liquor.Since we have failed to obtain consistent results by this method we have preferred to modify the pyridine method in such a manner that this difficulty is avoided by suitable choice of indicator; the procedure has been proved to be satisfactory in the examination of a large number of commercially dyed materials. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. REFERENCES L. L. Lloyd J . SOC. Dyers G. Col. 1914 30 12. J . Barritt J . Text. Inst. 1935 26 8 7 ~ . S. R. Trotman and G. N. Gee J . SOC. Dyers &J CoE. 1932 48 321. L. Meunier and G. Rey Rev. Gen. Mat. Col. 1924 28 66. H.R. Hirst and A. T. King J . Text. Inst. 1926 17 1 0 1 ~ . A. Woodmansey J . Sac. Dyers 6 Col. 1918 34 172. A. Eavenson and J. W. Creely Amer. Dyes. Rep. 1936 25 719. Private communication to F.L.G. M. Harris R. Mease and H. Rutherford Amer. Bureau of Standards J . of Research, S. R. Trotman and A. Bramley ANALYST 1936 63 408. 1937 18 343. WOOL INDUSTRIES RESEARCH ASSOCIATION LEEDS THE BRADFORD DYERS ASSOCIATION LTD. BRADFORD THE GEIGY COLOUR Co. LTD. BRADFORD THE BRITISH COTTON AND WOOL DYERS ASsOCI-4TIoN MANCHESTER May 22nd 1938 D~sc~:ss~os Mr. S. R. TROTMAN in a written communication said that the wool used in his experiments had been purified by the oleic acid process recently described by Trotman and Stockerlo ( J . Text. Inst. 1938 1 4 8 ~ ; Abst.ANALYST 1938 758). Table IV in his paper showed that with comparatively small percentages of acid the results of the pyridine and sodium acetate processes agreed well but that when 4 or 5 per cent. of acid were present the pyridine results were low and a second extraction was necessary. The authors of the present paper stated that a large blank correction was required in the sodium acetate process and that this was found to be.erratic. In his experience the correction had always been between 0.4 and 0-6 ml. of ATA0 alkali; to be on the safe side he deducted 0.6 rnl. from the alkali titration number. Two points were of importance (i) freedom of the steam from carbon dioxide (ii) rate of distillation which should be about 45 minutes for 650 ml. of distillate. The acidity given in Table V in his paperlo by the distillation method in September 1937 was 3-07 per cent.Since then the sample had been in an air-tight receiver. On October 29th 1938 he had redetermined the acidity by the distillation method and had found 2.97 per cent. In the investigation of complaints of skin irritation etc. where dyed goods were concerned the deter-mination of acidity was admittedly difficult and must involve the titration of a coloured solution except when the sodium acetate method was used. Dr. H. E. Cox said that he would like to pay tribute to the valuable work done by the authors on a matter of considerable practical importance. He had some experience of the methods described and hitherto had preferred the distillation method; he found it reasonably accurate and it had the advantage that it could be combined with other tests and determinations.He thought however that the most important practical point was to establish what acid was present and what was a proper limit for such acid. So long as one did not know what amount of acid should be regarded as a maximum the accuracy of the determination within 0.1 per cent. or so was not material. Dr. Cox further asked the authors as to thei THE DETERMINATION OF ACID I N WOOL 797 experience of the development of acidity in dyed and undyed woollen fabrics due to the action of light. Also did they think that the acidic groups in the acid azo dyestuffs contributed materially to the titratable acidity ? In his experience the acidity of a dyed wool was often lower than that of an undyed-perhaps sulphited-garment yet complaint would be made of the acidity in the upper garment but not of that in the under-garment.He hoped in view of its industrial importance, that the authors would continue their investigations into the wider aspects of the subject. Mr. C. E. SAGE asked whether any tests had been made with wool “pulled” by fellmongers as distinct from “clipped” wool and said that the alkaline con-ditions under which the former was stripped caused the development of not only ammonia but a considerable amount of amino substances which might not always be removed in subsequent treatment. Mr. J. BARRITT replying to Mr. Trotman’s written communication said that the discrepancy in the results obtained by the sodium acetate and pyridine methods referred to by Mr.Trotman would appear to arise from the use of too weak a solution of pyridine this being emphasised with samples containing up to 5 per cent. of acid; this point was elaborated in the addendum to the paper and it should be noted also that in commercially finished materials the amount of residual acid did not reach 5 per cent. Referring to the blank correction he said that they had been unable to obtain uniform blanks and their experiments had covered the conditions laid down with respect to freedom from carbon dioxide and rate of distillation. In attempts to solve this difficulty variations in the rates of distillation had been made and were discussed in the paper. The sodium acetate method had a marked advantage inasmuch as the titration was conducted in a colourless solution but in their experience this advantage was discounted by the difficulties in obtaining reproducible values and by the low recovery of acid.The difficulty in the deter-mination of the end-point in certain coloured solutions when using the pyridine method was overcome by the use of thymol blue as indicator and during the examination of a large number of samples the authors had not come across a material in which the acid could not be estimated satisfactorily by this method. Replying to Dr. Cox Mr. Barritt said that the nature of the acid in the material might be deduced by making PH determinations of a water extract (1 g. in 50 ml.) and of this extract after tenfold dilution. The original PH value coupled with the difference on dilution enabled a distinction to be drawn between organic and strong mineral acids. The amount of sulphuric acid present in finished woollen material rarely exceeded 2.8 per cent. and 3 per cent. might perhaps be regarded as an upper limit. The quantities of formic and acetic acids found in materials were usually less than 1 per cent. Wool on exposure to light developed an acid reaction which could be followed by pH measurements. Some of this acid was in the first instance sulphurous acid as might be shown by the formation of azo sulphite on wool dyed with certain azo dyestuffs. Undyed wool might contain more acid than a dyed wool for one of two reasons (i) The wool might have been sulphur-bleached i.e. treated with sulphur dioxide or a solution of sulphurous acid. From such material up to 1 per cent. of sulphur dioxide could be expelled by dis-tilling the wool with dilute acids. The whole question of the condition of the sulphur dioxide absorbed during bleaching of wool was somewhat complicated ; it was discussed in detail by Elsworth and Phillips (J. Text. Inst. 1938 29 219~). (ii) A sample of undyed carbonised wool might if not washed off or neutralised, contain up to 7 per cent. of sulphuric acid but would not reach the consumer in that state. He (Mr. Barritt) could confirm all that Mr. Sage had said regarding the con-ditions in the pulling of fleeces but he had not made any special tests with the two types of raw wool

ISSN:0003-2654    

DOI:10.1039/AN9386300782

出版商:RSC    

年代:1938

数据来源: RSC

摘要:

798 COAKILL ANALYSIS OF COMMERCIAL LEAD Analysis of Commercial Lead BY E. A. COAKILL A.I.C. THE following scheme has been devised for the determination of the impurities commonly occurring in commercial lead the main objects in view being to avoid the use of unwieldy quantities such as are generally recommended without a corresponding sacrifice of accuracy and to enable an examination to be carried out with greater speed. A number of the methods are not new and have been included merely for the sake of completeness others have been modified and in one or two instances the reagent used is practically all that remains unchanged in the original method. Regarding the possibility of the interference of any one of the elements with the determination of another it was found that when the process was used for its specific purpose namely the determination of impurities in quantities usually occurring in commercial lead either no tropble was experienced or any interference could be inhibited.PREPARATION OF THE SAMPLE.-A transverse section about half-an-inch in thickness is cut from the centre of a pig the sample for analysis is obtained by making saw cuts with a hack saw blade the sawings are picked over with an electro-magnet to remove any iron and 25g. (or 5Og. if the lead is very pure and other quantities pro rata) are weighed and transferred to a beaker. The metal is dissolved in 120 ml. of dilute nitric acid (1 volume of sp.gr. 142 to 2 volumes of water) and the solution is gently boiled to expel oxides of nitrogen; except in rare instances the solution will be found to be quite bright but in the event of a slight opalescence having formed the solution must be allowed to remain on a hot plate until the supernatant liquid is bright after which it is usually possible to syphon off most of the clear liquid and filter the remainder which contains the hydrated stannic oxide on a retentive paper.The small precipitate is washed with 2 per cent. nitric acid only the washings are added t o the main filtrate and the hydrated stannic oxide is retained to be examined later for possible traces of antimony. To the clear nearly boiling solution of lead nitrate are added 40 ml. of hot dilute sulphuric acid (1 volume of sp.gr. 1-84 to 3 volumes of water) the precipitate of lead sulphate is cooled rapidly and filtered off on a Buchner funnel, about three washes with 1 :15 sulphuric acid are given and the total filtrate is in a shallow beaker of the “Baco” type until dense fumes of sulphuric anhydride appear.When cool the residue is diluted with water and made up to 100 ml. in a graduated flask. Four ml. of this solution correspond with 1 g. of the original metal and in the following determinations quantities are expressed in grams. Comparison in Nessler cylinders is usually required and it is necessary that the standards should be treated in the same manner as the unknown solution; in every instance therefore, the starting point of the standard should be dilute sulphuric acid equal in quantity t o that present in the assay. A still more satisfactory “blank” may be obtained by taking 25 g.of assay lead in which the very minute amounts of impurities have been carefully determined and treating this in the manner already indicated COAKILL ANALYSIS OF COMMERCIAL LEAD 799 DETERMINATION OF SILVER ON 5 GRAMs.-The measured quantity is trans-ferred to a small beaker a few drops of phenolphthalein solution are added the free acid is neutralised with dilute ammonia and then the solution is brought back to faint acidity with acetic acid and cooled; then ten to twelve drops of a 10 per cent aqueous solution of gum arabic are added. Six ml. of acetone are put into a Nessler cylinder followed by 0.125 ml. of a saturated acetone solution of P-dimethyl-aminobenzal-rhodanine (this is sufficient for 0-1 mg. of silver and is about 10 drops as delivered from an average 1-ml.pipette) the solution suspected of containing silver is then poured into the cylinder and the contents are well mixed. The orange colour of the reagent is changed to a more or less red tint according to the amount of silver present and this is estimated by adding standard silver nitrate solution to a blank prepared in exactly the same manner. It should be noted that the smaller the excess of the reagent added the more sensitive is the test and it is hardly necessary to mention that special care must be taken to exclude chlorides during all operations. DETERMINATION OF COPPER ON 2 GRAMS.-The portion for the determination is put into a Nessler cylinder free acid is neutralised with ammonia and the liquid is brought back to faint acidity with acetic acid after which 0.5 ml.of 10 per cent. aqueous solution of gum arabic is added followed by 4 to 10 drops of a 0.25 per cent. alcoholic solution of rubeanic acid according to the amount of copper present. A blank is prepared in the same manner and standard copper solution which must contain no free mineral acid is added until equal intensities of colour are obtained. P)ETERMIKATIoN OF BISMUTH.-MethOd 1 (a$$roximate) 0% 2 Grams.-The requisite amount is transferred to a Nessler cylinder and 2 ml. of a 20 per cent. solution of potassium iodide (containing a few drops of a saturated aqueous solution of sulphur dioxide)* are added. Standard bismuth solution is then added to a blank prepared in the same way until the colours match correctly. It may be of interest to record that recently a doubt arose concerning the bismuth-content of a consignment of oxide of lead supplied to the Railway Company by a well-known firm of maniifacturers; the latter made their analyses by the tedious B.S.I.method and the Railway Company by that just quoted with very comparable results. As will be seen from the tabulated results the figures are low, for it is almost impossible to prevent the occlusion of a portion of bismuth in the bulky precipitqte of lead sulphate and to prevent this the following method has since been devised and is recommended to supersede Method 1. Jdet?zod %-Five g. of lead are dissolved in 30 ml. of dilute nitric acid (1 vohrne of sp.gr. 1.42 to 4 volumes of water) the solution is diluted to about 80 ml.with hot water and dilute ammonia (sp.gr. 0.94) is added until most of the free acid is neutralised but no permanent precipitate is formed about 5 ml. being required. Dilute ammonium carbonate solution (one volume of saturated solution to 3 volumes of water) is then added to the boiling solution 1 ml. or less at a time until a small precipitate of possibly 0.2 to 0.25 g. remains after boiling for a quarter of a minute; without delay the precipitate is filtered on a smooth surface paper washed several * See ANALYST 1938 63 107 for notes on the use of sodium hypophosphite in place of sulphurous acid 800 COAKILL ANALYSIS OF COMMERCIAL LEAD times with hot water removed from the paper to the original beaker with a strong jet of water followed by 10 ml. of (1 3) sulphuric acid and boiled briskly for a few minutes.The liquid which should not be more than 30 ml. in volume is filtered to remove lead sulphate and made up to a definite volume and an aliquot portion is examined for bismuth in the manner already described dilution to at least 50 ml. being recommended should the solution be strongly coloured; by this means the whole of the bismuth is separated from the lead and if necessary the result may be obtained within an hour. TIN.-The question of the most satisfactory method of determining a trace of tin which may have escaped precipitation and therefore observation during the original solution of the metal is one that has not yet been satisfactorily solved, although tin may be detected comparatively simply as follows :-Strong hydro-chloric acid is added to a portion of the solution suspected to contain tin until about 25 per cent.by volume is present after which a coil of iron wire is introduced and heat is applied until a brisk action is obtained. When it is judged that the reduction is complete the solution which still contains the iron wire is cooled, preferably in an atmosphere of an inert gas rapidly filtered to remove copper, antimony etc. and mixed with a few drops of an aqueous solution of cacotheline; a more or less pronounced violet colour is obtained in the presence of tin but unfortunately it is not usually sufficiently permanent to allow of its use for quantitative purposes apart from the fact that the inevitable even though short exposure to air may oxidise part or all of the stannous compound before the addition of the reagent.More recently dithiol has been used for the detection of tin and whilst this appears to work quite well qualitatively I have been unable to obtain reliable quantitative results with it. The strength of acid recommended for dissolving the metal €or the main analysis is such that a mere trace of tin would not be precipitated and consequently, it is desirable to test say 50 g. of lead specially for that element by dissolving it in the least possible excess of nitric acid (sp.gr. 1.42) diluted with five times its volume of water (theory requires about 31 ml.). The hydrated stannic oxide, after separation may be dealt with by one of the usual methods it being borne in mind that it will almost certainly contain lead and possibly antimony.It is recognised that this is by no means an ideal method and it is hoped that before long it may be possible to recommend a reasonably reliable colorimetric one. DETERMINATION OF ANTIMONY ON 5 GRAMS-TO the solution contained in a small beaker is added about 0.1 g. of tartaric acid a few drops of phenolphthalein solution and 50 per cent. sodium hydroxide solution (weight/volume) from a pipette until the reaction is just alkaline and then four drops in excess. The beaker is then placed on the hot plate and treated with 5 drops of sodium sulphide solution (made by saturating 5 per cent. sodium hydroxide solution with hydrogen sulphide and afterwards adding 20 to 25 per cent. of its volume of the original sodium hydroxide solution).After digestion near the boiling-point for about ten minutes the coagulated sulphides are filtered off on a 7 cm. paper of close texture and the filtrate is collected in a Nessler cylinder cooled and treated with 10 drops of a 10 per cent. aqueous solution of gum arabic and 2 ml. of hydrochloric acid (1 1) COAKILL ANALYSIS OF COM[MERCIAL LEAL) 801 and the yellow to orange colour is compared with that of a similarly prepared standard of known antimony-content. The comparison should be made as quickly as possible owing to the fact that after some minutes colloidal sulphur may begin to appear and the smaller the excess of sodium sulphide that has been used and the colder the solution the longer will its appearance be delayed, It has been found that the most satisfactory method of preparing the solution for comparison is to have a known amount of antimony present in the form of a standard solution (say 0.1 to 0.2 mg.) while still in the alkaline condition and to form the colour by the addition of the acid as with the assay.It has been observed that on adding standard antimony- solution after the acid that is in the presence of the liberated hydrogen sulphide the colour obtained is of a somewhat browner tint than that normally produced but that the small additions necessary to obtain equal intensity of the standard and the sample do not materially affect the shade provided these additions are not excessive. Under the heading of “Preparation of the Sample” mention was made of the possibility of a small precipitate of hydrated stannic oxide which might also contain antimony and this may be dealt with by the above method with slight modifica-tions as follows:-The precipitate is ignited at as low a temperature as possible and fused with two or three pellets of potassium hydroxide in a silver crucible, the melt is extracted with water the solution is acidified with hydrochloric acid, and from this point the procedure is as described above except that sodium oxalate in the proportion of 0.1 g.per mg. of tin must be introduced to inhibit the action of that element; this must be done prior to the final addition of acid. DETERNINATIOW OF ARSENIC ON 2.5 GRAhis.-The appropriate volume of solution is transferred to a Nessler cylinder free acid is neutralised with strong sodium hydroxide solution the minimum amount of methyl red being used as indicator and the solution then adjusted with very dilute sulphuric acid until faintly acid.The liquid is then cooled to 20” C. or below one ml. of Deniges’ reagent (10 g. of ammonium molybdate in 100 ml. of water poured into 300 ml. of (1 1) sulphuric acid) is added followed by 4 drops of a 2 per cent. solution of stannous chloride in 10 per cent. hydrochloric acid the liquid being well stirred after each addition. A blue colour is produced in the presence of less than 0.006 mg. of quinquevalent arsenic but the maximum intensity is not attained until the lapse of some minutes after the addition of the stannous chloride. The standard containing quinquevalent arsenic is prepared in the same way and the stannous chloride is added to it and to the assay solution within a few seconds of each other; the quantity of arsenic likely to produce a depth of colour not very divergent from the sample is usually 0.005 to 0.01 mg.and comparison is made by diluting the more highly coloured solution. It must be remembered that differences of temperature acidity etc. between the sample and the standard render unreliable what is otherwise an accurate determination. The blue colour is also produced by phosphates but none of the impurities commonly occurring in lead appears to affect the result. DETERMINATION OF IRON ON 2 GRAMs.-Five ml. of (1 1) hydrochloric acid and 5 ml. of 10 per cent. potassium thiocyanate solution are added to the sample contained in a Nessler cylinder and the pink (or red) colour is matched by addin 802 COAKILL ANALYSIS OF COMMERCIAL LEAD standard ferric iron solution to a blank solution similarly prepared.If desired, the colour due to ferric thiocyanate may be extracted by shaking with amyl alcohol; this procedure renders the test more sensitive. Thioglycollic acid may also be used for the determination of iron but my experience of this reagent is not very extensive and the following details are given with reserve :-One ml. of 10 per cent. tartaric acid solution is added to the sample which is then made just alkaline with ammonia and when cool is treated with 5 drops of thioglycollic acid (90 per cent.) and the colour which may be lilac to violet according to the quantity of iron present is matched as described above.ZINC ON 2 TO 5 GRAMS (according to the amount of impurity expected).-A method for the determination of zinc by means of diphenylthiocarbazone was published by Hibbard? but separation from traces of lead was somewhat tedious and a speedier method was therefore sought. After a large number of experiments had been made it was found that a solution of 0.05 g. of diphenylthiocarbazone in 1OOml. of chloroform containing 4 per cent. by volume of thioglycollic acid not only preserved the reagent from oxidation but also inhibited the interference of lead sufficiently to render its complete removal unnecessary and it is upon this fact that the following procedure is based:-The quantity of the solution to be examined is transferred to a small deep beaker heated to boiling-point saturated with hydrogen sulphide to remove lead and other heavy metals as far as possible, and filtered the concentration of sulphuric acid being sufficient without any ad-justment to prevent the precipitation of the zinc.The filtrate is heated until the volume is reduced to about one-half or until all the hydrogen sulphide has been driven off and then cooled and about 0.5 ml. of 5 per cent. tartaric acid solution is added followed by ammonia until the reaction is just alkaline the minimum quantity of bromocresol blue being used as indicator. The solution is again cooled and transferred to a 50-ml. stoppered cylinder 5 ml. of chloroform and 1 ml of the reagent prepared as described are added the cylinder is shaken gently and the aqueous portion which will now probably be faintly acid is adjusted with very dilute ammonia until just alkaline.The cylinder is then shaken vigorously until no further colour change takes place. A blank solution prepared in the same way as the assay of the same alkalinity and containing exactly the same amount of reagent should be available and to this is added standard zinc solution with vigorous shaking after each addition until the colours of both standard and sample are the same. The comparison may be made either during or immediately after shaking and the strength of the standard solution should be varied according to the amount of theimpurity present. One ml. of the reagent is sufficient to inhibit the action of 0.4 mg. of lead and for the determination of about 0.1 mgm. of zinc; but it must always be in excess and more should be added before the colour, originally green approaches a true red.Sometimes sufficient iron may be present to produce a colour with the thioglycollic acid contained in the reagent in which event it will be first noticed in the aqueous portion when it is finally made alkaline. As the amount of iron present will then be known the same quantity is added to the blank in the form of standard iron solution and the aqueous portion is adjusted by means of very dilute ammonia or sulphuric acid until it shows no more than a faint pink colour which is maintained by further adjustment if necessary unti COAKILL 1 ANALYSIS OF COMMERCIAL LEAD 503 the conclusion of the test. In practice it is probable that the amount of iron present in most leads will not be sufficient to cause any interference.CADMIUM.-Whikt there are a number of reagents by means of which coloured precipitates may be obtained with cadmium all suffer either from insufficient sensi-tivity or lack of adaptability in minute quantities or both. For the determination of cadmium therefore it would seem that a larger quantity of metal must be examined and this element determined by one of the recognised means until such time as a reliable colorimetric method can be recommended. The following figures will serve as an indication of the accuracy to be expected. The first series of tests were made on assay lead to which were added impurities TABLE I PURE LEAD WITH IMPURITIES ADDED (All figures in parts per million) Impurity Silver Iron by t hioglycollic acid Iron by thiocyanate Copper Bismut h Method 1 Bismuth Method 2 (separate quantity) Arsenic Antimony Zinc Analysis No.1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 a b 1 2 3 4 1 2 3 4 1 2 3 4 c Amount of impurity added 20 20 40 40 10 20 30 50 10 20 30 50 40 50 50 60 40 50 80 120 50 100 200 2 4 6 8 20 40 40 80 8 10 20 40 Amount of impurity recovered 17 18 35 36 10 20 31 50 10 22 31 51 41 49 50 58 33 36 67 90 50 100 197 2 4 6 8 21 41 42 81 8 10 19.5 39. 804 COAKILL ANALYSIS OF COMMERCIAL LEAD in the form of standard solutions the volume of which was allowed for in the original solution in dilute nitric acid.A sample of the assay lead was treated in exactly the same manner but without the addition of any impurities and was used as a blank when making colour comparisons in order to counter the effect of any trace of impurity that it might contain. The second series was obtained by using low grade lead (the impurities in which had been determined by the foregoing process) and adding known amounts of standard solutions as in the first series; in some instances especially where dealing with the higher concentrations the quantities taken for examination were a half or even a quarter of those recommended. It will be noticed that the results for bismuth by Method 1 arc unreliable and that little more than 80 per cent.of the quantity added could be recovered; on the other hand the results by Method 2 may be regarded as quite satisfactorv. TABLE I1 IMPURE LEAD WITH IMPURITIES ADDED Impurity Silver Iron Iron Copper by thioglycollic acid by thiocyanate Bismuth Bismuth Method 1 (All figures in parts per million) A B Original Im-Analysis amount of purity S O . impurity added 1 5 20 2 5 40 1 3.5 10 2 1.5 20 1 3.5 10 2 1.5 20 1 25 40 2 42 20 1 142 20 2 126 40 Lf 152 50 C Total impusi ty found 23 44 13.5 22 13 20 67 63 156 160 202 Method 2 (separate quantity) B 152 200 350 Arsenic Antimony Zinc - 1 1 4 0 2 1 8 9 1 21 20 42 2 14 40 56 1 6 10 16 2 6 20 28.5 b Column D is C-A and in theory should equal B.D Added impurity recovered 18 39 10 20.5 9.5 18.5 42 21 14 34 50 198 4 8 21 42 10 20.5. A few remarks concerning the storage of standard solutions may be added. It has been found that very dilute solutions do not retain their original strength for long periods and that generally speaking it is more satisfactory to prepare “stock” solutions containing 1 mg. per ml. of the element concerned to store these in the dark and to dilute to one-tenth the strength for use (with arsenic an DUCKWORTH AND GODDEN DETERMINATIOK OF MAGNESIUM 805 possibly zinc to one-hundredth). It is claimed that after a fair trial the foregoing process u7ill be found to yield reasonably accurate results and to effect a very considerable saving of time and reagents when compared with other methods which involve the use of very large quantities of metal. In conclusion I wish to thank the following members of the Research Depart-ment I,ondon Midland & Scottish Railway Mr. \IT. P. Henderson Chief Chemist, Dr. P. Lewis-Dale late Chief Chemist and Mr. G. W. Jones Assistant Chief Chemist for reviewing the text and Mr. N. I. Hailey for his assistance in carrying out some of the very large number of experiments that were found to be necessary. REFERENCE 1. P. L. Hibbard Ind. Eng. Chenz. Anal. Ed. 1937 9 127. LONDON MIDLAND & SCOTTISEI RAILWAY h?ESEARCH DEPARTMENT STONEBRIDGE PARK .-lpYiE 193

ISSN:0003-2654    

DOI:10.1039/AN9386300798

出版商:RSC    

年代:1938

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-ction

ISSN:0003-2654    

DOI:10.1039/AN9386300805

出版商:RSC    

年代:1938

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

ISSN:0003-2654    

DOI:10.1039/AN9386300809

出版商:RSC    

年代:1938

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

ISSN:0003-2654    

DOI:10.1039/AN9386300815

出版商:RSC    

年代:1938

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-ction

ISSN:0003-2654    

DOI:10.1039/AN9386300816

出版商:RSC    

年代:1938

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

ISSN:0003-2654    

DOI:10.1039/AN9386300818

出版商:RSC    

年代:1938

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

ISSN:0003-2654    

DOI:10.1039/AN9386300821

出版商:RSC    

年代:1938

数据来源: RSC