74 



NATURE 



[November 23, 1905 



In referring to the construction which must follow 

 criticism, Mr. Sedgwick says : 



" That is the task of the great band of workers 

 in many departments of Biology, who, undeterred 

 by failure and urged ><n by the fire, enthusiasm, and 

 generous aspirations of youth, return time after time, 

 generation after generation, to the assault of the 

 fortresses of nature well knowing that their material 

 reward will be small, that defeat means the world's 

 neglect and that success, except the greatest, brings 

 but a pittance of its esteem. To them 1 inscribe this 

 book in the hope that it may serve if only to a small 

 extent to smooth over the difficulties of part of the 

 road which at first they have to travel." 



We may be allowed to thank the author for doing 

 more than " smooth over " the difficulties of the road 

 on which all students of zoology have to travel, for he 

 has cleared away many hindrances and pointed out 

 many pitfalls. It would serve little purpose, how- 

 ever, to enter into any discussion of the numerous 

 morphological problems in regard to which Mr. 

 Sedgwick has made some personal and luminous con- 

 tribution. We feel that we have not said enough in 

 regard to the excellence of his workmanship, but 

 praise of what is masterly is gratuitous. The book's 

 scholarliness, clearness, and carefulness of statement 

 are obvious, but those who work with it will discover 

 other virtues — a suggestive scepticism, a mature 

 judgment, and a more indefinable quality which we 

 can only hint at in the phrase " morphological 

 insight. " 



AN ESSAY IX HISTORICAL CHEMISTRY. 

 The Study of Chemical Composition: an Account of 

 its Method and Historical Development. By Ida 

 Freund. Pp. xvi + 650. (Cambridge: The Uni- 

 versity Press.) 

 \/\ ISS FREUND is to be congratulated on having 

 i^I written a very interesting book. It is true 

 that her subject-matter is to be found in many other 

 quarters; she has really written a historical treatise 

 on what is generally called stoichiometrv ; but having 

 chosen as her title "The Study of Chemical Com- 

 position," she has left herself, so to speak, unfettered, 

 and has been able to write somewhat more dis- 

 cursively than if she had compiled a treatise. 

 Indeed, in the preface to the work she confesses: — 



" Although anxious to trace separately tin- historical 

 development in the discovery and in the establish- 

 ment of certain laws and classes of phenomena, I 

 have made no attempt to produce anything sufficiently 

 complete or even sufficiently proportioned to deserve 

 the name of history. I have preferred to deal in 

 greater detail with a few researches, especially such 

 as I could repeatedly utilise from various points of 

 view, than to .. at a greater number more cursorily, 

 bslieving in what Lavoisier said more than a century 

 as, r o that ' in such matters as these, the choice of 

 proofs is more important than their number.' " 



The result is a fairly full, indeed in some instances 

 a very full, account of classical researches in the 

 sphere to which she has confined her attention ; the 

 only omission is that of all reference to the laws of 

 dilute solutions, and in this she was guided by the 

 NO. lSS->, VOL. 73] 



fact that the subject has been recently fully treated 

 in many works which are easily accessible. 



Beginning with a sketch of the method of the in- 

 ductive sciences, quotations from Bacon, Jevons, 

 Kant, Whewell, and Mill are introduced, with illus- 

 tration, ol deductive reasoning by Kepler, Lavoisier, 

 Davy and others, having as its basis classification, 

 generalisation, and law. Next follows a fairly de- 

 tailed study of the phlogistic theory, giving an 

 excellent summary of the views held bv the phlogis- 

 tonists. Here Cavendish's reasons for his choice of 

 the terminology of the phlogistic theory might 

 with advantage have been inserted. Examples of 

 Lavoisier's and Stas's work, and of Morley's syn- 

 thesis of water are given to illustrate the basis on 

 which the doctrine of the " conservation of mass " 

 is founded. But Laws may be of two kinds, exact 

 and approximate; the difference is illustrated by 

 Boyle's law and van der Waals's improved form. We 

 do not notice, however, the remark that van der 

 Waals's formula itself is only a rough approximation 

 to the expression of the behaviour of gases under 

 high pressures. Landolt's experiments, which may 

 be now accepted as a proof of the accuracy of the 

 constancy of mass, are cited; the reviewer does not 

 know if Landolt has published the fact that his doubts 

 disappeared only after he had used silica instead of 

 ;;lass vessels. 



Affinity is the subject of the next historical sketch; 

 here the views of Bergmann and Berthollet are very- 

 well summarised; and this naturally leads to the 

 conception of fixed ratios by Proust, and the succeed- 

 ing work of Dalton and Berzelius, with reference to 

 the ideas contended for bv Laurent. 



The author now harks back to theories of matter, 

 taking up the subject at its earliest start in India 

 and Greece. The speculations of Bacon, Descartes, 

 Gassendi, and Boyle are described, generally in their 

 own words. Next follows a full account of Dalton's 

 atomic hypothesis, of Gay-Lussac's law of volumes, 

 and of Avogadro's generalisation. Berzelius's atti- 

 tude towards the rival views is explained, and a clear 

 account is given of the veteran Cannizzaro's suc- 

 cessful attempt to obtain full recognition of the justice 

 of Avogadro's views, so long overlooked. The deter- 

 mination of atomic weight bv means of specific heat, 

 and an excellent account of Mitscherlich's work and its 

 latest development by Retgers (this last, so far as the 

 reviewer knows, has not previously been accessible 

 except in original papers), complete this part of the 

 subject. The periodic arrangement of the elements, 

 and its bearing on the determination of atomic- 

 weights, leads naturally to a consideration of the 

 doctrine of valency, and Miss Freund has not omitted 

 to state the attempts which have been made to re- 

 present valency in terms of the electronic theorv. A 

 chapter on isomerism follows, and the concluding 

 chapter treats of the constitution of matter and the 

 genesis of the elements. 



From this sketch it will be seen that Miss Freund 

 has brought together, in a compact form, a great 

 deal of Interesting matter. She has quoted freely 

 from the authors whose views she presents, and, on 



