lO 



NATURE 



\_April 5, 1 890 



readily destroyed, which may explain why they are 

 sometimes not easily detected. 



The avithor has done good service in threshing put all 

 the evidence afresh, but the matter remains very much 

 where Koch left it. The detection of the bacilli may 

 enable us more readily to diagnose the earliest cases in 

 an epidemic of cholera ; and, as one result of his experi- 

 ments, we may expect soiled linen to be most efficiently 

 sterilized by drying it ; at the same time, until the 

 disease has been reproduced by inoculation with the 

 organism, it cannot be said to be conclusively proved 

 that this is the true virus. 



OUR BOOK SHELF. 



Manuel de V Analyse des Vins. Par Ernest Barillot. 

 Pp. xii -131. (Paris : Gauthier-Villars et Fils, 1889.) 



The student of practical chemistry will find in this book 

 a handy guide to the examination of wines. Works on 

 the same subject are frequently rendered both unwieldy 

 and tiresome by a multiplicity of analytical methods and 

 the introduction of a bulky collection of tables embodying 

 the composition of various classes of wine, a knowledge 

 of which is deemed necessary in forming an opinion of 

 the quality or purity of a particular sample. Here, 

 however, details of this l<ind are reduced to a minimum. 

 One or two methods, only, of carrying out any estimation 

 are given, and free use is made of such empirical relations 

 between the proportions of the constituents of a wine as 

 seem warranted by the results of previous analyses. 



The book consists of two parts and an appendix. Part 

 1. is concerned with the determination of the normal 

 constituents of wines, alcohol, total solids, ash, grape 

 sugar, &c. Part II. deals with adulterations. In its 

 opening sections are placed the indications traceable to 

 the presence of added water, added alcohol, cane sugar 

 dextrine, &c., but the greater bulk of the part is devoted 

 to the detection of foreign colouring matters. The 

 subject of colour reactions is very fully treated, and by 

 the arrangement of the experiments in tabular form their 

 nature and interpretation can be readily appreciated. It 

 seems a pity that in connection with these tests no notice 

 is taken in the text of the absorption spectrum of the 

 colouring agents, as a clue to their identification ; in a 

 footnote the author contents himself by merely referrmg 

 the reader to the works of \'ogel and Wurtz for inform- 

 ation on this subject. In the appendix is a statement of 

 the chemical constitution'of the colouring matters men- 

 tioned, followed by an account of some recent work of 

 the author on the detection of added alcohol. His 

 method is based on the effect of the alcohol introduced 

 on the proportion of volatile acid which distils from the 

 wine, and the result is shown to be consistent with the 

 theory of the rate of etherification of organic acids. 



The book is intended to be useful for commercial 

 purposes, and for such the analytical processes described 

 are sufficiently accurate. The apparatus emplo)ed, as is 

 stated in a footnote, has been constructed by the Societe 

 Centrale de Produits Chimiques, and judging from the 

 illustrations, is in some cases, to English eyes at least, a 

 trifle antiquated. The occasional reference to vessels 

 provided with marks, and to which no numerical values 

 are attached, detracts somewhat- from the general useful- 

 ness of the book, and is unintelligible to a reader who has 

 failed to notice the explanatory footnote. 



The graduation of alcoholometers, the maximum 

 amount of alcohol permissible in wines, &c., are of 

 course in accordance with the regulations of the French 

 Excise. 



Synoptical Tables of Organic and Inorganic-. Chemistry 

 Compiled by Clement J. Leaper, F.C.S. (London: 

 George Gill and Sons, 1890.) 



The compiler says in his preface that "the mass of facts 

 presented to the mind of the beginner in chemistry is scv 

 large that he often experiences a difficulty in distinguish- 

 ing the useful from the ornamental, and is apt, conse- 

 quently, to neglect fundamental principles and reactions 

 for comparatively useless minutiae. These tables are 

 intended to prevent this error. . , . The experience of 

 many years has convinced the author that the student 

 who honestly commits these tables to memory will lay 

 for himself a solid groundwork for future reading and 

 research 1" Whatever may be meant therefore by the 

 expression "future reading and research," it appears that 

 the compiler aims no higher than to give a series of 

 unconnected statements which if learned will enable the 

 would-be student to begin his study of chemistry. We 

 do not think this committing to memory will make the 

 study more easy, and should fear that the learner might 

 imagine after his memory exercise that he thereby knew 

 something of chemistry. The separation of "the useful 

 from the ornamental " is always difficult, and it is rare to 

 find two authorities at one in such a matter. It is 

 doubtful, for example, whether any chemist will agree 

 with the compiler when he states as Charles's law that 

 "All gases expand or contract .l..; of their volume for 

 each rise or fall of i' C.,'' and omits, presumably as 

 ornamental, the limitation of this proportion to the volume 

 of the gas at o C. 



The British Journal Photographic Almanac, 1890. Edited 

 by J. Traill Taylor. (London : Henry Greenwood 

 and Co., 1890.) 

 In this year's volume we find a most interesting collection 

 of notes and articles relating to almost every branch of 

 the subject. Captain Abney contributes an article in 

 which he warns photographers to beware of their principal 

 enemy — dust — and concludes with the best method of 

 exclusion. The Rev. S. J. Perry gives a short summary 

 of the instruments used in celestial photography during 

 the past year, and of the work accomplished, including- 

 the wonderful photographs taken by Isaac Roberts of 

 the nebula of Andromeda, nebuke in the Pleiades, &c. 

 Mention is also made of the success of Mr. Common in 

 rendering still more perfect the reflecting surface of his 

 magnificent five-foot glass mirror. Amongst the other 

 articles we may refer to that on halation by Chapman 

 Jones, hydroquinone by W. B. Bolton, and celluloid films 

 by Colonel J. Waterhouse. An epitome of the year's 

 progress, with notes on passing events, original and 

 selected, is given by the editor, who marks the great 

 advance made in film photography, and also the tendency 

 to diminish the bulk of cameras, as shown by the innu- 

 merable hand or detective cameras that have appeared 

 during the last twelve months. Allusion also is made to 

 the new developer, eikonogen, which can, it is believed, 

 develop into full printing density a plate that has beei> 

 impressed by feeble radiations. 



No alteration has been made as regards the genera) 

 order of the work ; there are only slight additions to the 

 tables, formuht, &c. The specimens of processes which 

 illustrate the volume, especially that of Mrs. Sterling from 

 a negative by Vander Weyde, are very fine. 



Four-Figure Mathematical Tables. By J. T. Bottomley, 

 M.A., F.R.S., &c. Second Edition. (London: Mac- 

 millan and Co., 1890 ) 

 This useful collection of tables has been considerably 

 enlarged and revised since its first appearance. It com- 

 prises logarithmic and trigonometrical tables, tables of 

 squares, scjuare roots, and reciprocals, and a collection of 

 useful formulae and constants. The introduction is suffi- 



