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/AN9426700329

出版商:RSC    

年代:1942

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/AN9426700330

出版商:RSC    

年代:1942

数据来源: RSC

摘要:

BIOCHEMICAL Biochemical 333 Isolation of a Copper Bearing Protein from Cow’s Milk. W. L. Dills and J. M. Nelson. (J Amer. Chem. Soc. 1942 64 1616-1618.)-Cow’s milk contains 0-09-0.17 mg of inherent copper per litre (cf. Sylvester and Larnpitt ANALYST 1935, 60 376) and the present authors have isolated from milk a protein containing about 15% of nitrogen and 0.19% of copper the method of isola-tion being fractional pptn. with ammonium sulphate and solution of successive ppts. in 0.1M disodium hydrogen phosphate followed by removal of phosphate with basic lead acetate and pptn. of the copper-containing fraction with ice-cold acetone ; the material was finally purified by adsorption on alumina elution with 0.1 M disodium hydrogen phosphate and dialysis of the solution.Dialysis a t $H 6.5 showed the copper to be non-ionic. The protein was probably mainly a single chemical substance although insuflicient material was isolated to establish definitely that it was abso-lutely pure. It showed no enzymatic activity, which is probably not due to denaturation during isolation because other milk enzymes continued to accompany in the active form the copper-protein during isolation and also because the process of isolation was similar to those employed in the isolation of other copper proteins in their native condition. E. M. P. Estimation of the Plasma Proteins by the Salicylsulphonic Acid Reaction. C:A. Mawson (Biochem. J . 1942 36 273-280.)-Plasma proteins can be estimated with sufficient accuracy for clinical * purposes by measuring the optical density of the suspension produced by adding salicylsulphonic acid to a saline dilution of plasma.Dilute 0.2 ml of plasma with normal saline to 20 ml and to 1 ml of the soln. add 3 ml of 3% salicylsulphonic acid soln. Shake and leave for 10 min. then shake again and read the optical density in a Klett absorptiometer using an Ilford neutral grey screen (density 0-5) as standard with a n orange Ilford Spectrum filter to eliminate the effect of colour. The depth of the suspension% adjusted until th 334 ABSTRACTS OF CHEMICAL PAPERS brightness of the two fields seen in the eyepiece appears equal. The total plasma protein is given by the expression Optical density of screen Reading of absorptiometer (cm) x 22.2%. To determine albumins dilute 0.2 ml of the plasma to 5 ml with 22.2% sodium sulphate soln.leave for 3 hrs. a t 38" C. and filter a t this temp. through two No. 2 Whatman filter-papers to remove pptd. globulins. Estimate the albumins by diluting 0-5 ml of the filtrate with 0.5 ml of water add 3 ml of salicylsulphonic acid soln. leave for 40 min. and read the optical density as before. Total proteins in cerebrospinal fluid or urine are estimated by using 1 ml of each in place of the dil. plasma. The method was applied to 16 specimens of plasma with varying albumin/globulin ratios and the results were compared with the values obtained by the Kjeldahl method. All were good except in 2 expts. in which low unexplainable results for plasma albumin were obtained.Good agreement was also obtained in the estimation of known amounts of globulin added to dil. plasma and albumin filtrates. The mcthod is particularly suitable for the rapid assessment of the protein needs of patients receiving intravenous therapy. F. A. R. Acylation of Amino-acids by means of 3:5-Dinitrobenzoyl Chloride and certain other Acid Chlorides. B. C. Saunders G. J. Stacey and I. G. E. Wilding. (.Biochem. J . 1942 36 368-375.)-The identification and separation of amino acids by reaction with 3 5-dinitrobenzoyl chloride was described by Saunders (Biocheun. J . 1934 28, 580; J. Chem. SOC. 1938 1397; ANALYST 1934 59, 568) and Town (Biochem. J. 1941,35,578; ANALYST, 1941 66 384). The 3 5-dinitrobenzoyl derivatives of dl- valine m.p. 227.6 to 228.6" C.dl-norleucine, m.p. 186" C. dl-cr-amino-n-hexoic acid m.p. 203.5-204" C. and glycine m.p. 179.5" C. are now described. The m.p. recorded for the first two compounds differ from those given by Town. The 3 6-dinitrobenzoyl derivatives of certain amino acids can exist in different forms particu-larly when hydrates are formed and this detracts from the value of the reagent for amino-acids generally. 3 5-Dinitrobenzenesulphonyl chlor-ide is too unreactive for use in the identification of amino acids whilst methanesulphonyl chloride, which is very reactive towards hydroxyl ions and is useful for the identification of certain phenols gave amino acid derivatives that were very soluble in water; the reagent is also less reactive towards the amino group than towards the hydroxyl group.a-Toluenesulphonyl chloride was somewhat less reactive than methanesulphonyl chloride. F. A. R. Determination of Methionine. E. F. Beach and D. M. Teague. ( J . Biol. Chem. 1942 142, 277-284.)-Not all protein preparations give satis-factory results by existing methods for determining methionine and a new method has therefore been devised. This comprises dcmethylation of methio-nine with hydrodic acid which a t the same time converts the resulting homocysteine into a homo-cysteine-thiolactone ring compound. This does not form a cuprous mercaptide whereas cysteine, which does not yield a thiolactone ring compound, reacts with cuprous oxide to form an insol. mer-captide. If the homocysteine-thiolactone compound is treated with alkali the ring is opened and on.treatment with cuprous oxide the cuprous mer-captide of homocysteine is pptd. together with that of cysteine. The difference in the- weight of the mercaptides before and after treatment with alkali is equiv. to the methionine content. Weigh out a sample of the protein containing approx. 6mg of methionine add 25 ml of conc. hydriodic acid and heat under reflux for 18 hr. Evaporate under reduced pressure a t about 40" C. to 0.5 ml and add. several lots of 2.5y0 hydrochloric acid with repeated distillation to remove the iodine. Transfer to a 250-1111 centrifuge bottle and dil. to 50 ml. Add an excess (about 2 g) of moist silver chloride and shake vigorously to remove hydriodic acid using additional quantities of silver chloride to ensure that thc rcmoval is complctc.Ccntrifuge off the silver iodide decant the supernatant liquid through a filter and wash the residue with water. Evaporate. the filtrate and washings to a syrup under reduccd pressure transfer the syrup to a 50-ml graduated flask and dilute to the mark. Pipette 25 ml into a stoppered centrifuge tube and rinse the pipette into the graduated flask with a little water. Add to the first aliquot portion 1 ml of 25% hydriodic. acid and 300mg of zinc dust and stand a t room teniperature for 2 hr. Filter adjust the filtrate. t o pH 4 to 5 by means OC saturated sodium acetate soh. and add a cuprous oxide suspension dropwise with stirring until a small excess is present. Centri-fuge off the ppt. and wash three times with 30 ml of citrate and acetate buffer solution (dissolve 12 g of sodium citrate and 16 g of citric acid in 200 ml of water add 20 ml of glacial acetic acid and dilute tenfold for use) to remove sulphur contaminants, Determine the sulphur micro-gravimetrically and, calculate the cysteine content froni the result.Adjust the second aliquot portion to neutrality by addition of 5 N sodium hydroxide and add 1 ml in excess. Leave for 15 min. to open the thiolactone ring acidify with 2 1111 of 20% hydrochloric acid, add 300mg of zinc dust and leave the mixture overnight a t room temp. After heating for 2 hr. in a steam-bath decant from excess zinc into a centrifuge tube containing a few drops of the cuprous oxide suspension wash the zinc with water, and decant the washings through a filter into the centrifuge tube.Stir the cuprous oxide suspen-sion for 15 sec. and centrifuge for 1 min. with minimum exposure to air. Washing with buffer soln. is unnecessary. ppt. also is determined micro-gravimetrically and the result is a measure of the amount of cysteine and homocysteine present. Some loss of methionine occurs during the hydriodic acid treatment and a factor of 1.11 must be applied to correct for this loss the recovery of pure methionine being 90% of the theoretical. 1 mg of BaSO = 0.515 mg of cysteine or 0.709 mg of methionhe (corrected) and the yo methionine in a protein sample The sulphur content of this I mg RaSO from second portion - mg BaSO from first portion g of sample - - x 0.142, Duplicate estimations agreed well and recoveries of added methionine ranged from 96 to 103"/ of the theoretical.Cystine recoveries were low from 80 to lOOyo of the theoretical. The following values were obtained for the methionine contents (yo) of several proteins arachin 0-57 ; casein 3.12; edestin, 2.30; egg white 4.09; gelatin 0-81; human globin, 1.52; lactalbumin 2.98; beef muscle 3-21. F. A. R BIOCHEMICAL 335 Modified Procedure for the Colorimetric Estimation of Arginine and Histidine. H. T. Macpherson. Arginine.-The a-naphthol method for estimating arginine involves errors as the colour is rapidly destroyed by excess hypobromite and this is not corrected merely by rapid addition of the urea used to destroy the excess reagent. In the method proposed the urea is added before the hypobromite and the colour is built up in two stages.This .ensures max. and consistent colour development, the colour is stable and the results are' not affected by slight deviations from the conditions. When using a 10-mm cell as little as 0.02 f 0.001 mg can be estimated. Transfer an aliquot part of the soln. containing 0.04-0-40mg of arginine to a 25-ml flask and dilute to about 10ml. I f acid, make alkaline to litmus by adding 10% potassium hydroxide soln. drop by drop and add 1 ml in excess. Add 2ml of O.l')'o cc-naphthol soln. in 50% alcohol and 1 ml of 40% urea soln. followed, .after cooling by 1 ml of potassium hypobromite soln. ( 2 g of bromine in 100ml of 5% potassium hydroxide soln.). After 2 to 5min.add another 1 ml of urea soln. and then 1 ml of hypobromite soln. make up to vol. and leave for 10-15 min. Measure the extinction coefficient in a Pulfrich photometer using filter 553 and a 10-mm cell with water in the compensating cell and calculate the .arginine content from a standard curve. Histidine. -Estimation of histidine by means of the colour reaction with diazotised sulphanilic acid has the .drawbacks that the colour fades rapidly and varies in intensity with slight differences in the alkalinity .of the soln. A method is therefore recommended i n which (a) the reaction between the histidine and the diazotised sulphanilic acid is carried out a t room temp. (b) sodium carbonate is used as the .alkali and (c) the colour is stabilised by addition .of alcohol.Transfer an aliquot part of the soln., containing 0.01-0.20 mg of histidine to a 25-ml flask and make just acid to litmus by addition of 10% hydrochloric acid. Dilute to 10 ml add 1 ml of 1% sulphanilic acid in 10% hydrochloric acid followed by 1 ml of 5% sodium nitrite soln. Leave for 30 min. a t room temperature and add 3 ml of 20% sodium carbonate soln. Mix add 10ml of 75% alcohol containing 1 ml of 20% sodium car-bonate soln. per 100 ml and dilute to vol. Measure the extinction coefficient using filter S53 and a 10-ml cell and calculate the histidine content from a standard curve. Polarographic Determination of Citrinin. H. W. Hirschy and P. M. Ruoff. ( J . Anzev. Chem. Soc. 1942 64 1490-1491.)-Citrinin, C,,H,,05 is a yell'ow cryst.solid m.p. 170"-171" C. (decomp.) and a metabolic product of PeniciZZium citrinum ; i t inhibits the growth of Staphylococcus aweus (cf. Raistrick et al. Phil. Trans. 1931, B220 269; Chem. and Ind. 1941 60 828; 1942,' 61 22). Well-defined polarographs are obtained with buffered and unbuffered 0-001-0.003 M solns. in 75% ethanol and the limiting current is propor-tional to the citrinin concn. ; the half-wave potential at $H 2.05 is in the range -0.80 to -0.82 volt (sM. calomel electrode). Solns. of citrinin in a 0.1 N soln. of potassium chloride in 75% ethanol are reduced but solns. in alcoholic buffer solns. of PH 6.0 (acetate) or 7.4 (phosphate) are not. Titanium trichloride cannot be used for the potentio-metric standardisation of thc method because stable potentials cannot be obtained within a reasonable time.Citrinin is a fairly strong acid (Biochem. J. 1942 36 59-63.)- ' F. A. R. (K 5.5 x a t 21" C. in 95% ethanol). Below pH 4.6 its solns. have a bright lemon-yellow colour and green fluorescence; a t pH 4.6 the colour begins to fade; at pH 5.6-5.8 i t changes sharply to orange-pink; above pH 9.9 this changes sharply to cherry red. J. G. Inter-Relationship of Vitamins A and E. K. C. D. Hickman P. L. Harris and M. R. Woodside. (Nature 1942 150 91-92.)-Since vitamin E can preserve vitamin A in oil solution and increase its store in rat liver (Davies and Moore, id. 1941 147 794) an interdependence of these vitamins which should be apparent in other respects is suggested. The effect of a widc range of vitamin E dosage on the growth of young rats depleted of vitamin A is shown by graphs relating the change in body wt.in 28 days for supplements to the U.S.P. basal diet (vitamin A assay) of 0-4 mg/day of a mol. distillate containing 40% of mixed tocopherols. The vitamins A used were the pure cryst. alcohol the cryst. acetate and a mixture of 90% of 6- and 10% of a-carotenes. The curves show a pronounced synergistic effect especially with the carotene, i.e. a quantity which was unable to support life alone induced good growth when fed with sufficient vitamin E. The optimum supplement of toco-pherols (which was not critical) was 0.1 0.15 and 0-6 mg/day for these 3 vitamins A respectively, corresponding with 0-6-3.0 mg/day/kg of body wt. This mutual effect persists with high levels of vitamin A intake and is more pronounced if the vitamins A and E are fed simultaneously than if fed on alternate days.There is evidence that vitamin E preserves vitamin A primarily before and during intestinal absorption but also a t the site of utilisation in the body; also that an acute shortage of either vitamin will result in the deficiency symp-toms of the other. It therefore seems necessary to modify the accepted methods of bio-assay of these vitamins since e.g. by manipulating the vitamin E content of the diet in a comparison of the U.S.P. Reference Oil JI with carotene apparent potencies varying from 700 to 4,000 I.U. are ob-tainable. Similar results were obtained with mink and rclated fur-bearing animals but the expts.have not yet been applied to farm animals or to humans. If these behave similarly it may be possible to relieve doubts whether a well-balanced diet can supply optimal amounts of vitamin A by attention to the vitamin E content. J. G. Chemical Determination of Aneurine. E. R. Kirch and 0:Bergeim. (1. Bid. Clzem. 1942, 143 675-58S.)-Dilute the solri. containing 3 to 1Opg of aneurine to 26 ml and add 100/ acetic acid to bring the pH to ca. 5 followed by 5 1111 of a diazo soh. preparcd by mixing equal vols. of a 0.5% soln. of the trichloroacetate of ethyl 9-aminoben-zoate in 95% alcohol and a 0 . 6 ~ o soln. of sodium nitrite in 8.5 to 90% alcohol. (The ethyl p-amino-benzoate trichloroacetate is prepared by dissolving 16.5 g of ethyl +minobenzoate in 250 ml of 2y0 hydrochloric acid adding an aqueous soln.of 16-3 g of trichloroacetic acid stirring and filtering; the salt is recrystallised from 95% alcohol). Leave the mixture for 2 mins. make alkaline with N sodium hydroxide and after a further 2 min. to allow max. colour development shake the soln. with 5 ml cf isoamyl alcohol. Separate the two layers dry the alcoholic layer over sodium sulphate, and measure the intensity of the colour in the Pulfrich photometer calculating the results from a standard curve prepared with pure aneurine soln 336 ABSTRACTS OF CHEMICAL PAPERS Very few substances interfere with the reaction, and with most of the substances that give a colour this is not extracted by isoamyl alcohol. Adrena-line gives a red colour sol.in the alcohol but this disappears in 8 to 12 hrs. whilst resorcinol phloro-glucinol and phenol in strong soh. also give colours, which fade after 14 hrs. Hence in presence of such impurities the soln. should be allowed to stand overnight before measuring the colour. Vitamin A interferes and should be removed by extraction with isaamyl alcohol before adding the diazo reagent and ascorbic acid prevents the development of the colour and should be destroyed by oxidation with 1 % potassium permanganate soln. a t pH 4.5 the slight excess of permanganate being decolorised by adding 2 ml of 1% sodium bisulphite soln.; the diazo soln. is then added and the colour is measured in the ordinary way. Ribo-flavin and othcr components of the vitamin B, group do not interfere.Cocarboxylase does not react with diazotised ethyl p-amino-benzoate so that free aneurine can be estimated in presence of its pyrophosphate and the total (free and com-bined) aneurine can be estimated by repeating the procedure after hydrolysis with phosphatase. The hydrolysis can be effected either by heating the soln. with fresh live yeast for 2-3 min. in a boiling water-bath or by treatment in the cold with a yeast phosphatasc preparation; 30% alcohol is the best solvent to use in both instances. Thc method can be used for the estimation of cocarboxylase in yeast. To determine aneurine in urine adjust the pH to 3 with sulphuric acid concentrate under reduced pressure a t 60-60" C. to a tenth of the original vol. filter and extract an aliquot portion of the filtrate with isopropyl alcohol.Dilute a 5- or 10-ml portion of the concentrate to 20m1, adjust to pH 5-6-6-0 add 1% potassium per-manganate soln. until a faint pink colour pcrsists, and then add 2 ml of freshly preparcd 1% sodium bisulphite soln. and 5 ml of the diazo soh. Com-pletc the reaction in the usual way leaving the coloured soln. for about 8 hrs. beiore measuring the colour. Recoveries of added aneurine were 98% of the theoretical. F. A. R. Simple Method for the Clinical Estimation of Ascorbic Acid in Whole Blood. J. Deeny, E. T. Murdoch and J. J. Rogan. (Biochem. J . , 1942 36 271-272.)-The method depends on the suppression of ascorbic acid oxidation by saturation of the blood with carbon monoxide. Transfer 2 ml of oxalated blood to a test-tube 2 cm in internal diameter and add 2 drops of octyl alcohol.Bubble coal gas through the blood for lOmin., add 4ml of glass-distilled water and after passing the gas for a further 5min. add 2ml of 32% metaphosphoric acid. After mixing add 2 ml of 2 N sodium acetate transfer to a centrifuge tube and centrifuge. Titrate 2 ml of the supernatant liquid with 2 6-dichlorophenolindophenol soln. (1 ml = 0.01 mg of ascorbic acid) measuring the indicator from a 2-ml microburette. At the same time titrate to a faint pink colour a blank con-sisting of a 2-ml sample of a mixture of 6 ml of water 2 ml of metaphosphoric acid and 2 ml of sodium acetate solution. The estimation should be carried out as soon as possible after collection of the blood and care should be taken to avoid haemo-lysis.If the coal gas contains hydrogen sulphide, it should be bubbled through alkali solution. When known amounts of ascorbic acid were added to different samples of blood the error did not exceed &4%. I?. A. R. Vitamin C in Rose Hips. M. Pyke and R. Melville. (Biochenz. J. 1942 36 336-339.)-The vitamin C contents of hips from 16 species of British roses were determined by separating the flesh from the seeds grinding the flesh with powdered quartz in presence of 100 ml of a 5% soln. of sul-phuric acid containing 2% of freshly dissolved meta-phosphoric acid diluting to 500 ml and titrating 5 ml of a freshly prepared soln. of 2 6-dichloro-phenolindophenol with the clear centrifuged soln.Considerable variations were observed in the vitamin C contents which werc closely correlated with the latitudinal ranges of the different species. Thus the ascorbic acid content of 4 species indi-genous to Scotland and the north of England avcraged 1,000 mg and over per 100 g of flesh, whilst a second group containing between 600 and 1,000 mg per 100 g comprised species character-istically English and extending only to the south of Scotland. Two species containing less than 250 mg per 100 g were confined to southern England. Variations occurred within each group and thcse are attributed partly to varying degrees of ripeness in the hips and partly to the difficulty of distinguishing hybrids from parent species. Thc highest valucs recorded 1870 and 1820 mg per 100 ml flesh are for Rosa Sherardi and R.coriifolia but these are much lower than the values recorded for hips from northcrn Russia. A number of hips from foreign rose species were also examined and some of these werc found to be considerably richer than the native species. One of them a Turkestan species B. Fedtschcnkoana grown at Kew had an ascorbic acid content (4800 mg per 100 g flesh) as high as any recorded for Russian rose hips. Parsley as a Rich Source of Vitamin C. E. J. Morgan. (Nature 1942 150 92-93.)--Vitamin C contents of parsley previously recorded are 280 (India) 196 (S. Africa) and 176 and 180 mg/100 g (America). Data now obtained for-9 samples of leaves picked in Cambridgeshire in mid-April to early June 1942 are 250.00-333.28 (mean 279.5 mg/100 g; mean water-content, 80-20%).One sample of stalks (April 1942; water-content 85.14%) contained 66.40 mg/100 g. These vals. rank parsley higher even than ripe blackcurrants as a source of vitamin C (cf. Olliver, ANALYST 1938 43 2). The determination was made by extracting the ground sample with tri-chloroacetic and metaphosphoric acids and titrating the extract rapidly with 2,6-dichlorophenol indo-phenol (cf. Birch Harris and Kay i d . 1933 58, 490) ; it was unaffected by reduction with hydrogen sulphide or by treatment with mercuric acetate. No seasonal effect was evident for the period con-cerncd. T t is suggested that the consumption of parsley should be encouraged since 0.5 oz./day/ person provides the complete vitamin C require-ment; parsley is also rich in available iron (1.42 mg/ oz.).Chopping results in loss of the vitamin owing to irreversible oxidase action( cf. Pyke id. 1942, 236) and 30 min. after the dry leaves had been chopped with a sharp stainless steel knife it had fallen from 250.00 and 275.84 to 205.24 (mean) and 222.40 mg/100 g respectively; thcrc was no further loss in the next 2.5 hrs. A parsley beverage contain-ing 80-112 mg of vitamin C per pint is made by adding 1 pint of boiling water to 2 oz. of leaves and squeezing the mixture through muslin after 2 min. Fluor-imetric Method for the Estimation of Riboflavin in Foodstuffs. M. Swaminathan. F. A. R. J. G BIOCHEMICAL 337 (Indian J . Med. Res. 1942 30 23-35.)-A new fluorimetric method for the estimation of riboflavin has been devised involving (a) adsorption of ribo-flavin on fuller’s earth followed by oxidation o€ interfering pigments in the cold with dilute potas-sium permanganate solution; (b) measurement of the fluorescence after destruction of riboflavin by heating with 0.1 N sodium hydroxide soln.in a boiling water-bath for 40 min. to determine the interference due to blue fluorescent substances which are resistant to such treatment; (c) measure-ment of the fluorescence after addition of a known amount of riboflavin to the final extract to deter-mine the interference due to stable interfering pigments; (d) estimation of the recovery (%) of riboflavin added to the original foodstuff to deter-mine the losses in the process of extraction and purification.As riboilavin is photo-sensitive all operations should be carried out in subdued light, and solns. stored in a dark cupboard. Transfer 2 to 100 g of finely powdered or minced material, containing 30 to 1OOpg of riboflavin] to a beaker and add 200 to 500 nil of 0.05 N sulphuric acid. Heat a t 70-75” C. for 20 min. with stirring cool, centrifuge and extract the residue twice more with dilute acid. If the combined extracts are highly coloured add a slight excess of N lead acetate in N acetic acid centrifuge and wash the ppt. with 200 ml of water containing 20 ml of the lead acetate soln. If the substance is only slightly coloured, this stage is unnecessary. Shake the clear centri-fugate with 2 g of fuller’s earth for 5 min. transfer to a tall beaker and after standing for 15 min., decant the supernatant liquid into the shaking-bottle and shake with 2 g more of fuller’s earth.Decant the supernatant liquid into the beaker, centrifuge off the fuller’s earth and wash it with 10011~1 of 0.1 N acetic acid. Add 60ml of 50% aqueous alcohol and 2 ml of 10 N sodium hydroxide to the activated earth shake vigorously for 3 min. and then centrifuge a t high speed for 5 min. Transfer the centrifugate immediately to a conical flask containing 10 ml of 10 N acetic acid and elute the residue twice more in the same way with 0-5 ml of 10 X sodium hydroxide. Divide the combined eluates into two equal portions. Transfer one half (soln. B,) to a 250-ml beaker after adjusting to pH 10 and make more strongly alkaline by adding 0.5 ml of 10 N sodium hydroxide for every 100 ml of soln.Heat on a boiling water-bath for 40 min. to destroy the riboflavin cool acidify with Fml of 10N acetic acid and add sufficient 50% aqueous alcohol to restore the bulk of the original vol. To this soln. and t o the other half of the eluate (soln. T,), add 5 ml of 3% potassium permanganate soln. and, after standing for 1 min. add 10 ml of hydrogen peroxide soln. (12 vol.). Add 5 and 15 ml. re-spectively of 4 N sodium acetate to solns. B and T and after filtering dilute to 200ml. Repeat the procedure exactly as described on a further sample of the foodstuff to which 50pg of riboflavin havc been added thereby obtaining solns. B and T,. Transfer 11 ml of acetate buffer soln. (pH 5) to the cell of a fluorimeter and record the reading (a).Add 1 nil of a standard soln. containing 5pg of riboflavin to 10 ml of acetate buffer and take a second reading (b). Measure also the fluorescence of the solns. obtained by adding 1 ml of water to 10 ml of solns. T,,B, T and B (t, b, t, b,) and finally the fluorescence of the solns. obtained by adding 1 ml of the standard riboflavin soln. to solns. T, B, T2 and B (t’l b; t’ and b’,) making 10 readings in all. The riboflavin content of the sample is calculated as follows: fluorescence due to 5pg of riboflavin fluorescence due to 10 ml of soln. T, corrected for stable interfering substances = b - a . x (b - a) - 4 - - t’ - t, fluorescence due to 10 ml of soln. B similarly corrected fluorescence due to 10 ml of soln.T similarly corrected - - t2 x (b - a) t‘ - t2 fluorescence due to 10 ml of soh. B similarly corrected x (b - a) - b2 -0’2 - b, The difference between ( 2 ) and (3) gives the fluorcs-cence due to 10ml of extract corrected for alkali-table i ntcricrjng fluorescent substances whilst the difference between (4) and (5) gives the fluorescence due to 10ml of extract and added riboflavin similarly Corrected. The difference between these two vahies multiplied by the dilution factor and divided by (b - a)/G gives the amount of riboflavin recovered from that originally added to the sample, whence the yo recovery can be calculated. The correct riboflavin content per g of foodstuff is obtained by subtracting (3) from (a) multiplying by the appropriate dilution factor and dividing by the weight of the sample and the value of (b - a ) / 5 , and then dividing by the yo recovery.The results obtained by this mcthod corresponded well with the results of biological assays on siniilar materials recorded in the literature. The riboflavin contents of 3 samples of dried yeast were 55.6 64.8 and 27.5, of wheat 1.2 raw milled rice 0.3 parboiled milled rice 0.8 rice polishings 3 red gram 2.5 and ragi 0-5pg per g and of whole milk 1.5pg per ,rnl. Vegetables and fruits were poor sources of ribo-flavin. F. A. R. Fluorimetric Estimation of Riboflavin in Urine. M. Swaminathan. (Ibid. 37-43.)-Urines and extracts of urines purified by adsorption on fuller’s earth contain various amounts of colour-ing matter and bluc fluorescent substances which interfere with the colorimetric and fluorimetric estimation of riboflavin.The procedure recom-mended above for foodstufls can be applied to urine. Transfer 25-ml portions of 24-hr. specimens of urine to four small conical flasks labelled T, B,, T and B, and add known amounts of riboflavin to flasks T and B,. Adjust the urine in flasks B, and U to pH 10 by addition of 10 N sodium hydroxide add a further 0.7 ml and heat the flasks in a boiling water-bath €or 40 min. to destroy the riboflavin. After cooling add 3 ml of 10 N acetic acid to all four flasks. Add to flasks TI and T, the total quantity of alkali addcd to flasks B and B, and then add 4ml of 3% potassium perman-ganate soh. to all four flasks to oxidise interfering pigments followed after 1 min.by 8 ml of hydrogen peroxide (12 vol.). Add sufficient 4 N sodium acetate soln. to all the flasks so that the ratio of the conc. of sodium acetate to acetic acid is 7 3 and the pH about 5. Filter make up each soln. t o vol. and use 10 ml for measurement of the fluores-cence as described in the preceding paper. If the concn. of riboflavin is less than lpg per ml th 338 ABSTRACTS OF CHEMICAL PAPERS method developed for foodstuffs should be used as the amount of riboflavin present is too small to be determined accurately by the above method. The error of the method is l0-15%; it has been used to measure the riboflavin excreted by normal individuals before and after administration of a test-dose. F. A.R. Colorimetric Method for the Determination of the K Vitamins. J. V. Scudi and R. P. Buhs. ( J . Biol. Chew,. 1942 143 665-669.)-Attention was previously directed (cf. ANALYST 1942 67 173j to the influence of certain naturally occurring quinones such as tocopheryl quinone on the estimation of vitamin K by oxidation of the reduced vitamin with 2 6-dichlorophenolindophenol. It was found that these interfering substances reduced the indicator much more slowly than did reduced vitamin K and the data now presented confirm this. For a fixed concn. of vitamin K (12pg per ml) the quantity of vitamin estimated from the 3-min. reading ranged from 102% in presence of 4-8pg of tocopheryl quinone per ml to 125% in presence of 19.2pg per ml. With decreasing concns.of vitamin K and increasing concns. of the interfering sub-stance the errors were still larger. It was found that the error could be eliminated by extrapolating the time-colour intensity curve to zero time. The formation of tocopheryl quinone during the prep-aration of vitamin K concentrates for analysis can to a large extent be avoided by working in nitrogen under reduced pressures in absence of light. The use of hydroquinone as an anti-oxidant is also advantageous and this is removed quantitatively by the treatment with Claisen's alkali. The procedure is of course useless when tocopheryl quinone and similar compounds are already present in the substance and no method has yet been dis-covered by which they can be eliminated. F. A. R. Forensic Forensic Chemical Examination of Materials containing Soaps.11. Turbidimetric Deter-mination of Soaps. M. W. Partridge. (Quart. J . . Phartn. 1942 15 119-126.)-The standard acidimetric methods are not sufficiently specific for the determination of soap in cases of criminal abortion but a suitable turbidimetric method has been developed. Turbidity is measured in a Spekker photoelectric absorptiometer having neutral colour glass filters. Expts. were made on two types of soap solns. one containing 0.25 mg each of curd soap and hard soap per in1 of alcohol (25%) and the other containing 0-5 mg of soap per nil of alcohol (25%) calculated as sodium oleate and prepared from a mixture of 2 parts of oleic acid and 1 each of palmitic and stcaric acids. Pptn.with hydrochloric acid and calcium chloride was investigated. With hydrochloric acid the turbidity of the suspension is directly proportional to the logarithm of the time allowed for its forma-tion over a period of 6 to 25 min. so that regular values would be obtained after 10 min. ; moreover, any error in recording the time is minimal a t this point. With calcium chloride the turbidity is directly proportional to the logarithm of the time between 6 and 14 min. the best results again being obtained after 10min. The optimum concn. of hydrochloric acid is 0.2 N and of calcium chloride 5 to 70 mg in 50 ml. The recommended procedure is as follows :-Dilute the soap s o h containing 0.5-2 mg of soap to 50 ml with water a t 20" C. and add 5 ml of 2 N hydrochloric acid or 5 ml of 0.1 N calcium chloride drop by drop with constant stirring and leave the mixtur; for 10 min.Com-pare the turbidity with that of a standard soln. prepared in the same way or construct a calibration curve. A standard soln. of soap gave almost theoretical results by this method and commercial soaps treated with hydrochloric acid as pptg. agent and with a mixture of curd soap and hard soap as standard gave reasonably good results. When calcium chloride was used as precipitant, however and the standard was a soln. of sodium oleate palmitate and stearate the results were less satisfactory. Good results were obtained with aqueous solns. of commercial soaps but the method could not be used for the detection of soap in stains on fabrics. (Cj. ANALYST 1942 67 305.) F. A. R. Agricultural Some Observations on Carotene Losses in Storage. R. 0. Davies. (Chem. and Ind. 1942, 61 275-276.)-Carotene loss in dried lucerne, ground fairly fine and packed in three-ply valve type paper sacks varies with the temperature of storage. As the meal has an insulating effect sacks in the interior of a stack cool only slowly if stacked hot and carotene loss is greater than in sacks on the outside or on the floor. Sacks of meal with a carotene content of 290-305mg per kg and a moisture content of 2.89-5-77y0 were stacked a t 82"-103" F. (mostly over 90" F.); after 8 months, carotene loss in outside sacks on the floor was 15-40y0 and in inner sacks 50-70y0. Two special sacks cooled before storing and completely exposed to the air during storage lost 19% and 30%. In a second expt. sacks of meal with a carotene content of 392 mg per kg and a moisture content of 2.4% were stacked a t 65-70" F. After 5 days' storage the carotene content was 371 and after 17 days 304mg per kg; no further loss occurred up to 87 days. To reduce carotene loss therefore sacks of meal should be cooled before stacking. E. M. P

ISSN:0003-2654    

DOI:10.1039/AN9426700333

出版商:RSC    

年代:1942

数据来源: RSC

摘要:

338 ABSTRACTS OF CHEMICAL PAPERS Organic Determination of Fluorine and other Halo-gens in Organic Compounds. P. J. Elving and W. B. Ligett. ( I n d . Eng. Chem. AnaZ.'Ed., 1942 14 449-453.1-1f the sample is a liquid draw 0-10-0-15 g into a tared ampoule (diam. of bulb, 6-8; length of stem 50-60 mni) blown from 3-mm Pyrex tubing seal tubing seal the ampoule taking care to avoid decompn. of the sample and reweigh. Place the ampoule in a reaction tube with 5 ml of ether and 0.3-0-5 g of potassium in very small pieces and draw off the ether by connecting the tube through a water-trap to an aspirator; this also removes all oxygen and water-vapour and produces a low pressure so that explosion risks are decreased vaporisation of the sample is more rapid, the surface of the metal remains clean and is there-fore more reactive and the glass is less likely to be attacked.Seal the tube before disconnecting it, break the ampoule by shaking and place the tube in a furnace a t 400" C. for 15-30 min. (vide infra). Open the tube decompose the excess of potassium by cautious addition of ethyl alcohol and transfer the contents to a 100-ml beaker. Filter through a sintered glass crucible (size No. 4) neutralise the filtrate with nitric acid and determine the halide INORGANIC 339 directly in aliquot portions of the same soln. by any convenient method e.g. chloride bromide and iodide gravimetrically by pptn. as silver salts and fluoride by pptn. as lead chlorofluoride (cf. Hawley, ANALYST 1926 51 426). If nitrogen is present, interference by the resulting cyanide ion must be avoided but this ion does not interfere with the fluoride determination.Solids having an ap-preciable vapour pressure a t room temp. are sealed in tube-shaped ampoules having a fragile rounded end and the wt. of the evacuated ampoule must then be corrected for the buoyancy error so involved by adding rZTZd where Y and I are the internal radius and length in cm of the ampoule respectively, and d is the density of the air in g/ml. Gases are condensed before transference to the ampoule ; the substance of lowest b.p. which was sampled by this method was dichlorofluoromethane b.p. - 30" C. Potassium is preferable to sodium since it flows more freely and coats the reaction tube giving a large area of clean surface.With the exception of 6-chlorocoumarin 15-min. a t 400" C. sufficed for the fusion of substances containing only chlorine brom-ine or iodine. A special fusion furnace is described. Data are given for 24 purified aliphatic aromatic ali-cyclic and heterocyclic organic compounds contain-ing ll-20-69-57~o of halogen; the errors varied from & 0.02-0.34%. The best results were obtained when only a single halogen was present; when chlorine and fluorine were both present the silver chloride ppt. was coloured and the results high. The max. (negative) errors were obtained with gaseous chloro derivatives of the fluoromethanes, but these may have arisen through sampling and decompn. while the ampoule was being sealed. J. G. Identification of Amides through the Mercury Derivatives.J. W. Williams W. T. Rainey Jr., and R. S. Leopold. ( J . pmey. Chem. SOG. 1942, 64 173%1739.)-Many amides can be identified by conversion into mercury derivatives with charac-teristic m.p. Two procedures are recommended. (1) For all aliphatic amides and many aromatic amides.-Heat 1-5 g of amide and 0.5 g of yellow mercuric oxide over a small flame a t the m.p. of the amide until all the oxide has reacted (disappear-ance of colour) and all the water vapour has been expelled; add more mercuric oxide in small portions until no more reacts ending with an excess of amide. Cool somewhat take up in the min. amount of boiling ethanol cool and filter; wash the crystals with cold ethanol or ether. Purify by recrystallisation from ethanol or by leaching with hot ethanol (for derivatives of p-anisamide Yn-chloro-benzamide and benzenesulphonamide) .(2) For amides the mercury derivatives of which are soltcble in hot ethanol insoluble in cold (benzamide p-chloro-benzamide the bromobenzamides the toluamides, o-anisamide and salicylamide) .-Add 5 g of yellow mercuric oxide and 4 g of amide to 50ml of 95% ethanol reflux for 1 hr. filter hot through a fluted filter-paper chill in an ice-bath and remove the crystals by suction. Purify when necessary as in (1). The following (uncorr.) figures are given for m.p. and mercury contents of mercury derivatives : acetamide 196-197" C. mercury content found, 57.8% 58.5% (calc. 58.2%); propionamide 201" C.; benzamidc 222" C. 45.1% 45.2% (45.5%); m-chlorobenzamide 245" C.39-0y0 38.6% (39.2%) ; o-toluamide 196" C. 42.4% 42.5% (42.6%) ; o-anisamide 241" C. 39-8% 40.3% (40.1%) ; p-anisamide 222" C. 39-9% 40.3% (40.1%) ; salicylamide 190" C. 42.7% (42.4y0). E. M. P. Po-yok Fruits from Sierra Leone. (Bull. Imp. Inst. 1942,40 99-103.)-Two samples recently examined contained 59.6 and 67.7% of kernels yielding 51.2 and 54.8% of oil respectively. The oils gave the following values sp.gr. a t 15.5" C., 0.9619 0.9593; n;O 1.6160 1.5175; acid Val., 2.9 5.8; sap. Val. 189.9 191.5 iodine Val. (Wijs, 1 hr.) 148.2 150.1; unsap. matter 0.8 .0.7%. Under laboratory conditions a film of the dried oil became skin-dry in 24 hrs. but was not quite dry in less than 10 days. Films containing 0-1% of cobalt (as naphthenate soln.) dried in 24 hrs.but "webbed" like raw tung oil films. 'I'he samples formed gels on heating but these were sticky and could not be cut with a knife. In the heat test the unpolymerised oil gave higher results (44.9 and 52.5%) than the usual figure of about 20y0 for tung oil. Expts. indicated that po-yok oil has valuable varnish and paint-making properties superior to those 01 linseed oil but not equal t o tung oil (cf. Steger and van Loon ANALYST 1939 64, 703). E. B. D. Fibre Identification Stain. H. L. Davis and H. J. Rynkiewicz. ( I n d . Eng. Chem. Anal. Ed., 1942 14 472.)-The two Hahn stains recommended by the TJ.S. National Bureau of Standards for the identification of rayons (ANALYST 1939 64 425) have been combined and slightly modified so as to obtain a greater range of application and selectivity. The new stain contains:-Acid fuchsin (C.I. No. 692) which is more sol. than eosin 6 ; picric acid, 10; tannic acid 10; National Soluble Blue 2 B Extra (C.I. No. 707) 5 g. Grind these together and dis-solve them in 1 litre of hot water. Bleach the sample if necessary and immerse i t momentarily in the hot soln. ( 2 min. for cold dyeing) rinse well, and press between white absorbent payer. Colours obtained are :-Cotton or linen light blue acetate or nylon pale greenish-yellow cuprammonium, dark blue; viscose lavender; vinyon very pale blue ; wool yellow; raw silk black; degumined silk brown. Corresponding results are obtained with films of cellulose acetate or of viscose J. G

ISSN:0003-2654    

DOI:10.1039/AN9426700338

出版商:RSC    

年代:1942

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/AN9426700339

出版商:RSC    

年代:1942

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/AN942670342b

出版商:RSC    

年代:1942

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/AN9426700344

出版商:RSC    

年代:1942

数据来源: RSC