THE ANALYSIS OF SYNTHETIC DETERGENTS •59.7 the inorganic content of the precipitate can be calculated. The rest of the precipitate comprises the non-ionic surface active agent the content of which in the original solution is thus determined. An analysis of the precipitate is essential for every new type of non-ionic compound, because the value of x varies from one substance to another, and may even vary among com- pounds of nominally the same composition. Ml•. D. B^ss: Your method of analysis for ampho!ytics is to estimate as cationics under acid conditions. This method works well for the sub- stituted amino acid type, but do you obtain good results using the betaine type of ampholytic ? I am thinking in particular of difficulties when there is a degree of internal compensation within the molecule as with the cyclo- imidinium type. T}m LECTURER: Yes, we find our normal method for cationics to be satisfactory for the betaine type of surface active agent. The two-phase titration is performed in acid solution with chloroform as the organic phase, sodium dodecylbenzenesulphonate as titrant, methylene blue as indicator, and we take complete transference of colour to the organic phase as the end-point. BOOK REVIEW Standard Methods of Chemical Analysis. Volume II (A and B). INDUSTRIAL & NATURAL PRODUCTS & NONINSTRUMENTAL METHODS. Sixth Edition. Editor: F. J. Welcher. Part IIA--Pp. xiv q- (1-1282) q- Ill. Part IIB--Pp. xi q- (1283-2613) q- Ill. (1963). D. Van Nostrand Company, Inc., New York. $25 each (not sold separately). It is almost twenty-five years since a revised edition of Standard Methods of Chemical Analysis has appeared. In 1939, the Fifth Edition was published as two volumes but so great have been the modifications, refinements and developments of the methods of chemical analysis since that time that the Sixth Edition appears in three volumes, with Volume II expanded into two parts, bound separately as Volume IIA and Volume IIB. Despite its considerable expansion the purpose of Volume II remains that it shall be a collection of carefully selected well proved methods of technical analysis, of practical value to the professional chemist. The lay-out of this edition is similar to the previous one, but the expansion due to the inclusion of new material adequately reflects some of the important changes that have taken place in recent years in analytical techniques. The expansion includes chapters on standard laboratory apparatus detection of cations and anions mechanical separation separations by filtration separations by electrolysis solvent extraction separations by distillation and evaporation chromatography ion exchange methods in analysis acid-base titrations in non-aqueous solvents statistical interpretations quantitative organic analysis air pollutants amino acid analysis of protein hydroly- zates chemical analysis in clinical medicine fertilizers gas analysis with emphasis on vacuum techniques pesticides plastics silicates, glasses, rocks, soils and vitamins. There are numerous references to original papers and there is a good index at the end of Part B only. It is somewhat annoying that Part B has to be consulted for work that is known to be found in Part A, for these books are not lightweight ones. It is difficult to understand why the index was not included in Part A as well the book would only be 22 pages larger than Part B had this been done. Cosmetic chemists may be disappointed that the analysis of cosmetics does not

THE ANALYSIS OF SYNTHETIC DETERGENTS •59.7 the inorganic content of the precipitate can be calculated. The rest of the precipitate comprises the non-ionic surface active agent the content of which in the original solution is thus determined. An analysis of the precipitate is essential for every new type of non-ionic compound, because the value of x varies from one substance to another, and may even vary among com- pounds of nominally the same composition. Ml•. D. B^ss: Your method of analysis for ampho!ytics is to estimate as cationics under acid conditions. This method works well for the sub- stituted amino acid type, but do you obtain good results using the betaine type of ampholytic ? I am thinking in particular of difficulties when there is a degree of internal compensation within the molecule as with the cyclo- imidinium type. T}m LECTURER: Yes, we find our normal method for cationics to be satisfactory for the betaine type of surface active agent. The two-phase titration is performed in acid solution with chloroform as the organic phase, sodium dodecylbenzenesulphonate as titrant, methylene blue as indicator, and we take complete transference of colour to the organic phase as the end-point. BOOK REVIEW Standard Methods of Chemical Analysis. Volume II (A and B). INDUSTRIAL & NATURAL PRODUCTS & NONINSTRUMENTAL METHODS. Sixth Edition. Editor: F. J. Welcher. Part IIA--Pp. xiv q- (1-1282) q- Ill. Part IIB--Pp. xi q- (1283-2613) q- Ill. (1963). D. Van Nostrand Company, Inc., New York. $25 each (not sold separately). It is almost twenty-five years since a revised edition of Standard Methods of Chemical Analysis has appeared. In 1939, the Fifth Edition was published as two volumes but so great have been the modifications, refinements and developments of the methods of chemical analysis since that time that the Sixth Edition appears in three volumes, with Volume II expanded into two parts, bound separately as Volume IIA and Volume IIB. Despite its considerable expansion the purpose of Volume II remains that it shall be a collection of carefully selected well proved methods of technical analysis, of practical value to the professional chemist. The lay-out of this edition is similar to the previous one, but the expansion due to the inclusion of new material adequately reflects some of the important changes that have taken place in recent years in analytical techniques. The expansion includes chapters on standard laboratory apparatus detection of cations and anions mechanical separation separations by filtration separations by electrolysis solvent extraction separations by distillation and evaporation chromatography ion exchange methods in analysis acid-base titrations in non-aqueous solvents statistical interpretations quantitative organic analysis air pollutants amino acid analysis of protein hydroly- zates chemical analysis in clinical medicine fertilizers gas analysis with emphasis on vacuum techniques pesticides plastics silicates, glasses, rocks, soils and vitamins. There are numerous references to original papers and there is a good index at the end of Part B only. It is somewhat annoying that Part B has to be consulted for work that is known to be found in Part A, for these books are not lightweight ones. It is difficult to understand why the index was not included in Part A as well the book would only be 22 pages larger than Part B had this been done. Cosmetic chemists may be disappointed that the analysis of cosmetics does not