110 THE ANALYST. R E V I E W S . DETERMINATION OF RADICLES IN CARBON COMPOUNDS. By Dr. H. MEYER (Prague). Authorized translation, by Dr. 5. BISHOP TINGLE (Chicago). New York: J. TViley and Sons ; London : Chapman and Hall, 1899. This small book is a valuable addition to literature, containing as it does witbin the limits of 120 pages much useful information and many valuable hints. Its scope is broader than might be inferred from the title; it really deals with the principles of methods for the proximate analysis of organic compounds. Although it might appear at first sight to appeal more particularly to the investigator in organic chemistry than to the technical analyst, it must not be forgotten that the problems with which both are confronted very frequently differ only in the form in which they are presented.Methods which depend on the determination of certain atomic groups and radicles find in point of fact frequent application alike in purely scientific investigations and in the technical analysis of organic products. Some of these have, in their technical application, become quite stereotyped, and are perhaps too often used by analysts without regard to the scientific principles on which they are based. acetyl value,” ‘‘ iodine value,” convenient though they may be, are doubtless largely responsible for this, yet the analyst should in all cases consider what he is actually measuring. Thus, that the acetyl value is a measure of displaceable hydrogen in the groups - OH, = NH, etc., and that the iodine value indicates the presence of unsaturated compounds.To briefly summarize the contents of the book, it describes methods for the determination of the following groups : - OH, - OCH,, - OC,H,, - COOH, = CO, - NH,: - CN, - CONK,, = NH, = NCH,, the diazo, hydrazine, iodoso, iodoxy, and peroxide groups. Instructions are also given for the determination of the IC iodine value.” Methods for the determination of the basicity of acids, and for the introduction of acid radicles, notably acetyl and benzoyl, and of alkyl groups are fully described, and wherever chemicals rarely met with in laboratory practice are referred to, details for their preparation are given. The arrangement of the matter and the style of writing are all that could be desired, and the numerous references to original papers cannot but add to the utility of the book.The only typographical error noticed is on page 41, where the group carboxyl is represented as CHOR instead of COOH. Price 4s. 6d. The use of such terins as A. R. L. DAIRY CHEMISTRY: A PRACTICAL HANDBOOK FOR DAIRY CHEMISTS, ETC. By H. D. RICHMOND, F.I.C. London : Charles Griffin and Co., Limited. Price 16s. If the question were raised as to the necessity for a work specially treating on the chemistry of milk, it should certainly be answered in the affirmative. Not only is the public analyst called upon to examine large numbers of samples of milk and milk products with the object of detecting and checking adulteration, but other chemists are also frequently called upon to analyse and pass opinions on materials directly or indirectly connected with the dairy, and last, but not least, practical dairy work nowadays demands a considerable amount of scientific knowledge if itTHE ANALYST. 111 is to be performed in a satisfactory and successful manner.The days are gone for ever in which a very limited amount of experience was considered either sufficient to judge whether a milk was pure or sophisticated, or to support and aid the practical dairyman with scientific counsel, or to fill up a responsible position in the dairy industry. If, then, a work on dairy chemistry must be considered highly desirable-nay, necessary-nobody could be better fit for producing such a, work than the author of the book lying before us. Mr. Richmond has for nearly eight years superintended the Aylesbury Dairy Company’s laboratory, which was erected in the year 1880.Although established to serve the special requirements of that large firm in exercising an extended and minute control over the milk and milk products there dealt with, Mr. Richmond, like his predecessor, has not confined himself to exercising control alone, but has taken good care to make extensive use of the oppor- tunities given to work out as many questions as possible which in one way or another are connected with the chemistry of milk, milk products and dairy work generally. In the course of twenty years a vast amount of facts and experiences has been thus accumulated, which in itself would have been quite sufficient to form a valuable publication. By collating and studying the respective publications of others, and reproducing them in a digested form, he has succeeded in putting before the reader a complete work on dairy chemistry.I t would take up far too much space merely to indicate the contents of the various chapters of the book, to draw attention to the useful tables, and to enumerate the numerous illustrations. Less still could justice be done to Mr. Richmond’s work by an attempt to specially mention the most important parts and statements. I n fairness we must also abstain from noticing the weaker portions of the book, and as these are scant and of little importance we can do so without remorse. Suffice it to say that Richmond’s ‘‘ Dairy Chemistry ” forms a complete r6sum6 of theoretical and practical knowledge, written in easily intelligible language, and is a work useful to everyone desiring instruction in the chemistry of milk and milk products, a work which the A TEXT-BOOK OF PHPSI& CHE~VIISTRP.But the author has done much more. attentive reader will study with the greatest satisfaction. P. v. By Dr. R. A. LEHFELDT. London : Edward This branch of general chemistry has developed so enormously during the past twelve years or so that it now constitutes a department of considerable size and importance ; and as its teachings already to some extent exert on analytical problems an influence which in all probability will become more marked as time rolls on, it behoves every analytical chemist to become acquainted with the general principles of this subject, especially as analytical processes depend ultimately on a knowledge, not only of chemistry in the restricted sense, but of the physical behaviour of the materials dealt with. The work before us is eminently adapted for this purpose ; it forms a well-written digest, couched in terse but intelligible language. Although mathematical formulz are indispensable in illustrating a subject of this nature, the work is ingeniously arranged so as to be intelligible to the non-mathematical reader who is content to take the mathematical proofs on trust. The general get-up of the book is good; it is printed in clear, bold type, contains numerous illustrations and has a copious index. Arnold. Price 7s. Gd. W. J. S.