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424 REPORT ALCOHOLOMETRIC TABLES. By SIR EDWARD THORPE, C.B., F.R.S. London : Long- Price 3s. 6d. net. There has been a long felt want by chemists and technologists for a complete and trustworthy set of Tables of Alcoholometry based on a critical examination of the whole of the experimental data collected during the past hundred years or so. This want has been especially felt by those who require for their scientific researches the utmost refinement of accuracy in the observed relations between density and alcoholic concentrations.Up to recently the most complete and accurate Tables available have been those compiled in 1880 by the late Sir Thomas Stevenson, who states that for spirits ranging in specific gravity from 0-8250 to 0.9983 they were based on Blagden and mans, Green and Go, 1915.REVIEWS 425 Gilpin’s tables of 1794.The great accuracy of Blagden and Gilpin’s observations have been confirmed by all subsequent workers in this field, and especially by MendelBef. For spirits of less specific gravity than 0.8250 Stevenson made use of the data of Fownes, but he appears to have done this with a certain amount of distrust, since he was quite aware that the work of Fownes was much inferior in accuracy to that of Blagden and Gilpin.For spirits of higher specific gravity than 0-9983 Stevenson does not state his authority, but apparently his resnlts were calculated by extrapolation. In the Tables of 1880 the specific gravity of absolute alcohol is given as 0.7938 at 60’ F., compared with water at the same temperature, all weighings beings made in air ; but in the Preface to the second edition of his “Treatise on Alcohol,” pub- lished in 1888, Stevenson recognises that this value is somewhat too high, and in the body of the work he incorporates more recent investigations on this point, notably those of Messrs.Squibb. He did not consider it necessary, however, to alter the Tables published eight years previously, since he regarded them as ‘‘ sufficiently accurate for all practical purposes ; and the percentages of proof spirit so necessary to the public analyst, the brewer, the distiller, and the officers of Excise and Customs, are of course unaffected by the new determinations of the specific gravity of absolute alcohol.” During the quarter of a century which has elapsed since these words were written no further attempt appears to have been made to introduce a higher degree of accuracy into the Alcohol Tables until Sir Edward Thorpe undertook the laborious task of re-examining and criticising all the existing data.The result is now given in this little volume in the form of a, very complete set of Tables compiled under his direction by Mr.T. J. Chester and Mr. John Holmes of the Government Laboratory. They are preceded by a short Introduction giving a highly interesting summary of the progress of alcoholornetry since the year 1790, and an account of the standard fiscal spirits of various countries, and of the hydrometers used for the determination of their strength. The new Tables of Sir Edward Tborpe have been founded on the work of four authorities - Blagden and Gilpin, Drinkwater, Mendeldef, and the Kaiserlich Normal-Eichungs Kommission. The labour expended on their compilation must have been very great, entailing as it did the comparison and collation of a vast amount of experimental data, and their reduction to a uniform system ; but it has been well justified by the result, and from the experience of the writer of this notice it may confidently be stated that the Tables may be safely used in researches requiring a, high degree of scientific accuracy.The specific gravity of absolute alcohol at 15*6”/15*6” C. is taken as 0.79359 in air, a . value deduced from Mendeldef’s observations. The corresponding value for British Fiscal Proof Spirit containing 49.28 per cent, of alcohol by weight is 0.91976, against 0,9198 as given by Stevenson.Table I. gives for each interval of density of 0-0002 the percentage of alcohol by weight and by volume, and also the percentage of fiscal proof spirit, the specific gravities being determined at 60” 3’. or 1 5 6 O C. against water at the same tempera- ture. A comparison of this Table with that of Stevenson does not show many points4 26 REVIEWS of absolute agreement in the percentages of alcohol by weight.The differences as far as they have been tested appear to vary from about 0.10 to 0.01 per cent., but there is no consistent order in their distribution, and they are sometimes plus and sometimes minus. There is, as might be expected, a very much closer approximation to identity in the percentages of proof spirit as given by the old and the new Tables respectively, since any variation in the assumed specific gravity of absolute alcohol necessarily alters the standard value of proof spirit to a corresponding extent.Table 11. gives a synopsis of the standard fiscal spirits of Great Britain, America, Germany, and France, as compared with the indications of the Sikes hydrometer, which since 1816 has been the legal instrument for determining the strength of spirits for revenue purposes in this country. Table 111.gives a similar comparison of the readings of the Sikes hydrometer with the hydrometers in use in Russia, Holland, Spain, and Switzerland. All the Tables are printed in bold type, and in such a form as to admit of ready use. HORACE T.BROWN. ELEMENTARY CHEMICAL MICROSCOPY. By EMILE MONNIN CHAMOT. 1915. New York : John Wiley and Sons. London : Chapman and Hall, Ltd. Price 12s. 6d. net. The keynote of this work is to be found in the first paragraph of the preface, in which the author says: “ H e (ie., the American chemist) has also failed to grasp the fact that the modern microscope is in reality a more important adjunct to his laboratory than the spectrometer, poiarimeter, or refractiometer ; in fact, it way be said that the microscope is entitled to as important a place as the analytical balance.No one other instrument can perform so many functions and do them all well.” From this it will be inferred that the author is an enthusiast, and as such he possesses the defects of his qualities. I n food analysis, in biochemistry, in textile chemistry, and in toxicology, to name only a few departments of chemistry, the microscope has for long been recognised as an indispensable item of laboratory equipment.Many textbooks of varying degrees of excellence have been written, and nothing more is needed to emphasise the value to the chemist of microscopical investigation.It is not, however, with these highly important and more obvious uses of the microscope that the author concerns himself, but rather with the employ- ment of that instrument for the purpose of carrying out well-known chemical reactions on a very small scale, whilst he devotes some space to indicating how, by the exercise of ingenuity, the microscope may be made to do work for which it is not particularly well adapted.The limitations of the microscope as applied to chemical analysis are fairly well recognised, and if ‘the professional chemist does not more frequently utilise so-called micro-chemical reactions, it is because these are not as a rule sufficiently definite and specific. The difficulties, when working on a minute quantity of material, of separating in a state of purity any particular substance prior to applying microscopical tests, are so great as to render the method useless in the great majority of cases.It does, however, happen, notably in toxicological investigations, that micro-chemical indicrt-REVIEWS 427 tions are sometimes very valuable indeed, and there can be no doubt that the author is right in suggesting that the chemist might with advantage employ the microscope more frequently than he does.Whether or not the writer is correct in thinking that that portion of the book which deals with the micro-chemical reactions of the common elements will not prove to be of much value to the chemical practitioner, nothing but praise can be found for the remainder of the work, This is thoroughly well written, and embraces a clear and admirable exposition of microscopical technique.Even experienced microscopists could not fail to derive some useful information and many valuable hints from a study of it, whilst the average chemist will find that it constitutes a trustworthy and handy guide in his microscopical work. The print is clear, there ere very few typographical errors, there is a good index and the spelling is not aggressively Transatlantic.A. CHASTON CHAPMAN. THE CHEMISTS’ YEAR-BOOK, 1915. Edited by F. W. ATACK. Manchester : Sherratt Mr. Atack has hammered a highly commendable little nail into the coffin of German chemical indispensability by producing an excellent British substitute for the more familiar Cherniker Kalender.The 900 closely-printed pages contain vast stores of information upon all kinds of ohemical topics, and the concluding sections dealing with essential oils, textile fibres, synthetic dyestuffs, alkaloids, pharma- ceutical synonyms, trade names of drugs, indiarubber, tobacco, and photography, are valuable features. The discussion of indicators will bring joy to the heart of the ionophil, besides being serviceable to the mere chemist, and it is a useful idea to assemble the volume numbers of the principal journals against the year in which they are published.The lists of minerals, inorganic compounds and organic compounds with their properties, are very comprehensive, the last-named group including nearly 3,000 individuals ; in connection with the organic section, I would suggest the inclusion of the empirical formulae in place of the “ crystalline form and colour” column, which is not of any particular value, whereas in those cases where the constitution is complex the empirical formula would be helpful in the consulta- tion of Richter’s Lexikon, In war-time one searches naturally for a, section on explosives, and in consequence of its absence we are thrown back on the Daily Mail to inform us each morning why cotton should be contraband, and who is the greatest living ‘‘ scientist.” A more serious drawback is the obstinate inclusion of a diary which occupies 116 pages, and which, for at least two reasons, it is highly improbable that anyone will use : in the first place, most people note their most interesting engagements in the treasured intimacy of a waistcoat pocket, and then in war-time nobody should desecrate a 10s.6d. volume with ephemeral jottings. It is difficult to understand, also, why the editor clings so strenuously to the tongue-and-pouch fetish, with the inadequate pencil, because although they were a part of the Chemiker Kalender, a comparison unfavourable to Volume I.is imtituted by dividing the present work into two volumes and leaving the second volume in ordinary book form. and Hughes. 1915. Price 10s. 6d. net.428 REVIEWS The care with which the proofs appear to have been corrected is highly praise- worthy, because the tedium of checking so much tabular matter must be appalling, and tabular matter is valueless unless it is carefully checked.I t is to be hoped that, Mr. Atack’s applied patriotism will meet with the support which it deserves, not only from all British chemists who had found satisfaction in the Chemiker Kalender, but from those who, on general principles, recognise the vital necessity of supporting home industries from this time forth for evermore. M. 0. FORSTER. OUTLINES OF ORGANIC CHEMISTRY.By F. J. MOORE, Ph.D. Professor of Organic Chemistry in the Massachusetts Institute of Technology. Pp. xi + 325. New York : John Wiley and Sons, Inc. ; London : Chapman and Hall, Ltd. 1914. Price 6s. 6d. net. The author explains in the preface to the first edition that he annually delivers a course of about thirty lectures on the underlying principles of organic chemistry to a class made up of candidates taking their degree in Physics, Biology, and Sanitary Engineeripg. As these students need a knowledge of organic chemistry, but do not intend to become skilled organi,c chemists, the eubiect-matter is handled in a, different manner from thaf usually adopted when the primary object i s t o train organic chemists. I n dealing with a group of compounds, those substances are used as examples which are of more practical importance. The book has been foundedon the course of lectures and is very readable. The lectures themselves are based on a syllabus which comprises most of the subjects with which a scientific man who is not a speoialist in organic chemistry might: advantageously be acquainted. general knowledge of organic chemistry without specialising in the subject, The book should prove useful to those who desire J. T. HEWITT.

ISSN:0003-2654    

DOI:10.1039/AN9154000424

出版商:RSC    

年代:1915

数据来源: RSC