March 24, 1910] 



NA TURE 



95 



"The explanation of the loss or gain in weight on 

 burning tasked the best efforts of the whole scientific 

 world for -a couple of hundred years," 



and this is followed bj- an account of Priestley's dis- 

 covery of oxygen which even his greatest admirers 

 would scarcely sanction. After stating that Priestley 

 burned quicksilver in the air and obtained a red 

 powder, he goes on : — 



"The experiment so far was no different from 

 what had been done before, without result, but 

 Priestley, with that brilliant imagination which has 

 so often characterised the great leaders of science, saw 

 a new possibility. If mercury had changed to a red 

 ash by burning, could not the substance which had so 

 changed it be obtained from the red ash in its original 

 form by heating? " 



Cavendish's discovery^ we are told further on, 

 settled questions which had troubled men of science for 

 two centuries. To the question, "What is water?" 

 Cavendish gave the reply, " It is hydrogen oxide." 



Sufficient has been said to illustrate the peculiar de- 

 fects of the book, and it is not a little surprising that 

 none among the ten ladies and gentlemen named in 

 the preface to whom the MS. and proof were in turn 

 submitted should have directed the author's attention 

 to them. 



(2) Although we are deluged with books on qualita- 

 tive analysis. Dr. Caven's new volume may be regarded 

 as by no means a superfluous addition to the number. 

 He starts on the perfectly correct assumption that 

 qualitative analysis, properly studied, may serve as a 

 foundation for a sound knowledge of practical and 

 theoretical inorganic chemistr}\ and develops his 

 method along these lines. There is, of course, a great 

 deal about group reagents and tables of separation 

 •which are common to most books on the subject, but 

 there is, in addition, a useful general introduction, 

 which is clear and concise, and a final chapter on the 

 systematic examination of inorganic substances. The 

 author does not tell us for what class of student the 

 course is intended, and now that it is becoming the 

 fashion to serve up chemistry- to suit the diverse needs 

 of different classes of students, or, as someone ex- 

 pressed it, to sell it in assorted penny packets, we 

 doubt whether any but the embryo professional 

 chemist could give the time necessary- to complete it. 



It is doubtful, too, if it is desirable for any student 

 to postpone quantitative work until so much qualita- 

 tive analysis has been assimilated. 



Experience shows that an early acquaintance with 

 the former is an excellent discipline in careful mani- 

 pulation and exact observation, and the best antidote 

 to untidy and sloppy habits of work. J. B. C. 



OUR BOOK SHELF. 

 La Vita di Michele Faraday. Narrata da Andrea 



Xaccari. Pp. 370. (Padova : Fratelli Drucker, 



1908.) Price 3 lire. 

 Though there exist four well-known biographies of 

 Faraday in the English language, one only, the brief 

 essay by Tyndall, " Faraday as a Discoverer," has 

 been translated into Italian. Neither, until the appear- 

 ance of the work now under review, had any Italian 

 biography of Faraday been written. Prof. Naccari, 



NO. 2108, VOL. 8s] 



whose position as professor of physics in the Univer- 

 sity of Turin guarantees his competence in physical 

 science, and who is himself an experimental investi- 

 gator of some distinction, has now written a life of 

 Faraday which worthily presents the career of our 

 great countryman. He has drawn freely and with 

 due acknowledgment from all the four English bio- 

 graphies, and has had the advantage also of being 

 in possession of the volume of printed correspondence 

 between Faraday and Schonbein, which was published 

 more recently than any of the four. Thus, without 

 being either encumbered with the mass of details of 

 Bence Jones's authoritative memoir, or restrained 

 within the smaller compass of the three smaller bio- 

 graphies, he has been able to produce a work which 

 in certain aspects is the most satisfactory- life of Fara- 

 day yet compiled. He has not failed to incorporate 

 the newer material while preserving what was of 

 permanent value in the old. 



The life-story follows the familiar lines. The 

 author has not been able to add anything to our 

 knowledge of the doings or wanderings of Faraday 

 in Italy as the assistant of Da\y in his eighteen 

 months' tour of 18 13-15. Neither has he thrown 

 any further light upon the episode of the misunder- 

 standing between Faraday and Nobili and Antinori 

 in 1832 respecting their supposed correction of errors 

 which he had not committed. In the author's preface 

 he states that in his first ten chapters he has con- 

 sidered the man rather than the philosopher, with the 

 intention to make him known and to make him loved. 

 In his eleventh and last chapter, which occupies more 

 than one-third of the book, he treats of Faraday's 

 scientific work. Here he follows conscientiously and 

 skilfully the evolution of Faraday's discoveries 

 in their chronological order, but discusses them in 

 their relation to modern views and discoveries. He 

 lays great stress upon Faraday's electro-optic 

 pioneering discoveries as having been provocative of 

 so much of the later developments of physics. He 

 concludes by citing a characteristic passage from the 

 peroration of one of Faraday's last Royal Institution 

 discourses in 1858. 



The book is not illustrated by any cuts. It avoids 

 all mathematical expressions; but it is eminently 

 readable, and is well printed. English men of science 

 owe a debt of gratitude to Prof. Naccari for his faith- 

 ful presentation of one whose memcr\^ they so highly 

 honour. 



Botaiiisch-Mikroshopischer Praktikum fiir Anfdnger, 

 By Prof. Martin Mobius. Zweite Auflage. Pp. xi-h 

 123. (Berlin : Gebriider Borntrager, 1909.) Price 

 3.20 marks. 



The exercises, sixt}-four in number, contained in 

 this little book are designed to make the student 

 familiar with the outlines of plant structure in the 

 chief subdivisions of the vegetable kingdom. The 

 directions for making and mounting the preparations 

 are clear and good, and the text is not overburdened 

 with the details which the student ought to learn from 

 the preparations themselves. The illustrations, which 

 are diagrammatic, may also be found useful, although 

 we think the work would not have been impaired in 

 value had they been omitted. The fact that a second 

 edition has been reached proves that its author has 

 met a need felt for such a book, but it seems odd 

 to discover the statement that the aleurone-containing 

 cells of the castor-oil bean belong to the cotyledons 

 (Keimblatter). We also prefer the st\ie of Ranttn- 

 culus acris instead of R. acer (p. 9, &c.). But on the 

 whole the book is useful, well printed, and sensibly 

 bound, and its price is moderate. 



