NATURE 



529 



THURSDAY, APRIL 7, 1892. 



MENDELEEFF'S PRINCIPLES OF 

 CHEMISTRY. 

 The Principles of Chemistry. By D. Mendeldefif. 

 Translated from the Russian (Fifth Edition) by George 

 Kamensky, and edited by A. J. Greenaway. Two Vols. 

 (London : Longmans, Green, and Co., 1891.) 



ALL English-speaking chemists will cordially welcome 

 the appearance of this book, if for no other reason 

 than because its author in its preparation was led to the 

 recognition of that fundamental principle of chemistry 

 with which his name will always be associated — the 

 principle which is embodied in what is now known as 

 the periodic law. This fact alone would serve to stamp 

 the book as one of the classics of chemical science. 

 But, even apart from this circumstance, the work has 

 very remarkable, and, indeed, exceptional, merits. 

 Probably no scientific treatise ever more strikingly re- 

 flected the personality of its author. We have absolutely 

 nothing like it in our language. In grasp of principles, in 

 philosophic breadth, in copiousness of detail, in richness of 

 speculation and suggestion, it is altogether unique among 

 chemical manuals. Every true and earnest student of 

 chemistry is certain to be profoundly influenced by it, 

 even if he cannot always bring himself to subscribe to its 

 doctrine. Of course, the facts are, for the most part, those 

 which are common to all the larger treatises on systematic 

 chemistry, but these are set out and marshalled in a 

 manner wholly original. The intent and purpose of the 

 book is to demonstrate the broad general principles on 

 which chemistry as a science rests. This, it may be 

 urged, is the intent and purpose of every chemical treatise. 

 It may be so, but in many cases the philosophy is lost 

 sight of — obscured, indeed, by the facts, just as the houses 

 may obscure the view of the village. 



In Mendelcefif's work experimental and practical data 

 have their place, but only as means to an end, and that 

 end is as evident on every page as it was in Dalton's 

 immortal work. Fascinating as the book is, it must 

 be admitted that it is by no means easy reading ; 

 and he who wishes to master its contents and to 

 assimilate its teaching will need to gird up his mental 

 loins. Part of the difficulty is doubtless due to 

 the different genius of the languages, but much more 

 depends upon the impossibility of entering into the 

 spirit of an author, or of quickly realizing his drift and 

 meaning, when his whole mode of thought is so very 

 dissimilar to that which obtains among Western people. 

 It may be that herein lies part of the peculiar charm of 

 freshness of the work. The book of the Siberian chemist 

 is to the ordinary run of text-books what the novels of 

 Tolstoi or Turgenieff are to the common run of works of 

 fiction. But there are difficulties of another kind. Prob- 

 ably no other book in our language— certainly no other 

 chemical treatise— contains such an extraordinary num- 

 ber of footnotes. There is scarcely a page without a 

 footnote, and some of the pages are practically little else 

 than footnotes. The continuity of description or of 

 argument is constantly being broken, often by a footnote 

 NO. I 171, VOL. 45] 



extending over several pages, and frequently so diffuse 

 and involved that, by the time the reader has disposed of 

 it, the statement in the main text to which it had refer- 

 ence has been lost sight of, and must needs be picked up 

 again. Moreover, the repeated interruption is aggra- 

 vated by the circumstance that these notes are printed 

 in " nonpareil small," which adds enormously to the 

 physical fatigue of reading and studying the work. The 

 author, indeed, recommends that they should be read 

 only by the advanced student, or on a second perusal of 

 the work ; but we are afraid that no intelligent reader 

 will follow this advice when once he has begun to dip into 

 them. They are, in fact, like the postscripts of ladies' 

 letters— often more important, more instructive, more 

 suggestive, and more characteristic, than the main body 

 of the text. But, in truth, the book is not fitted for a begin- 

 ner : its proper readers are those for whom the footnotes 

 are specially intended. It requires, too, to be read with 

 discrimination. It was said by Davy that analogy is the 

 fruitful parent of error, and it must be confessed that 

 Mendeleeff's love of analogy frequently leads him to 

 generalizations which are more ingenious and suggestive 

 than intrinsically sound or well grounded. 



The translator and the editor have, doubtless, had 

 difficulties to contend with. They tell us that they 

 have not considered themselves at liberty to make any 

 alterations in the matter of the work, and they have 

 striven to give a literal rendering of it. They have felt 

 that, on the whole, it would be better to have some in. 

 elegance of language rather than risk the loss of the exact 

 shade of the author's meaning. Unfortunately, in too 

 many instances the translator and his editor have not 

 gained in precision of meaning what they have lost in 

 I elegance of statement. Thus, for example, on p. 12 we 

 read : 



" The means of collecting and investigating gases were 

 already known before Lavoisier's time, but he first showed 

 the real part they [the means or the gases?] played in 

 the processes," &c. 



) we 



On p. 19 it is stated : 



" By heating chalk (or else copper carbonate . 

 obtain lime," &c. 



Thus, too, on p. 47 : 



" In general terms water is called pure when it is clear 

 and free from insoluble particles held in suspension and 

 visible to the naked eye, from which it may be freed by 

 filtration through charcoal, sand, or porous (natural or 

 artificial) stones, and when it possesses a clean fresh 

 taste. It depends [what depends.?] on the absence of 

 any tastable, decomposing organic matter, on the 

 quantity of air and atmospheric gases in solution, 

 and on the presence of mineral substances to the 

 amount of about 300 grams per ton (or cubic metre, 

 or, what is the same, 300 milligrams to a kilogram or 

 litre of water), and of not more than 100 grams of 

 organic matter." 



Again, on p. 72 we read : 



"Although in the majority of cases the solubility of 

 solids increases with the temperature, yet, just as there 

 are substances whose volume diminishes with a rise in 

 temperature (for example, water from 0° to 4°), so there 

 are not a few solid substances whose solubilities fall on 

 heating. Glauber's salt, or sodium sulphate, historically 



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