July 15, 1897] 



NATURE 



247 



written for those who, without much previous acquaintance 

 with electrical apparatus, are for purposes of practical 

 utility or scientific recreation anxious for theoretical and 

 practical knowledge on the subject, this little book is 

 also replete with useful information and suggestive hints 

 that will not fail to prove of service to more experienced 

 electricians. The volume is methodically arranged and 

 well illustrated ; and if there are omissions which might 

 with advantage have been supplied, these are no doubt 

 largely due to the author having been confined to a 

 limited amount of space. So many experiments con- 

 nected with the electrical discharge in rarefied and dense 

 gases can be performed not only with an induction coil, 

 but equally efficiently with a Wimshurst or other form of 

 electrostatic influence machine, that one cannot but 

 regret that the author has so rigidly confined himself to 

 the application of coils alone. For a similar reason, it 

 seems a pity not to have included some detailed in- 

 formation as to the so-called high frequency coils of 

 Tesla and Elihu Thomson, which, even as an adjunct to 

 induction coils, are not quite so completely abandoned 

 for X-ray work as the author appears to imagine, while 

 they afford a means for many other instructive experi- 

 ments of comparative novelty and great beauty. It is 

 necessary to say, moreover, that the brief references that 

 do appear in the book to such coils, as also to the use of 

 alternating currents generally, are scarcely as accurate 

 and as lucid as might be desired. 



It is to be regretted that the author uses the word 

 current in a loose and, sometimes, in a very misleading 

 manner. Notwithstanding these defects, which it is to 

 be hoped the author may be able to remedy in subse- 

 quent editions, the book is undoubtedly the best popular 

 and practical work that has yet appeared on the subject 

 of which it treats. 



The Calculus for Ent^ineers and Physicists. By Prof. 

 Robert H. Smith. Pp. xi -V 176. (London : Charles 

 Griffin and Co., Ltd., 1897.) 



Not only is " Integration more useful than Differentia- 

 tion," the author's opening statement, but the conception 

 of Integration is more tangible and easy to grasp than 

 that of Dififerenliation, a far more abstract idea. 



We recognise the growth of a tree after a few years, 

 although the actual rate of growth is infinitesimal. 



For purposes of application, a knowledge of Differentia- 

 tion must just precede the inverse operation of Integration ; 

 but that does not justify our present system of carrying 

 the student through the Differential Calculus before start- 

 ing on the Integral ; the two subjects should be carried 

 out, as far as '^o'i^ixhXt., pari passu. 



Classified Reference Tables of Integrals form a feature 

 of this work ; and the author has also touched upon the 

 useful portions of Differential Equations. 



Any analytical difficulty is explained preferably by 

 means of a careful diagram (as might be expected from 

 an author of Graphical Calculus), and by intuitive reason- 

 ing, rather than by processions of unconvincing equations 

 and inequalties, employed by schoolmen of the pure 

 orthodox mathematical faith ; whose indulgence the author 

 begs in his Preface, asking them to remember that there is 

 arising a rapidly increasing army of men eagerly engaged 

 in the development of physical research, . . . whose 

 mental facilities have been wholly trained by continuous 

 contact with the hard facts of sentient experience, and 

 who find great difficulty in giving faith to any doctrine 

 which lays its basis outside the limits of their experiential 

 knowledge. G, 



Zur Zoogeographie der landbeiuohtienden Wirbellosen. 



Von Dr. Otto StoU. Pp.113. (BerHn : Friedlander, 



1897.) 

 The majority of treatises upon geographical distribution 

 have used as facts and framed their conclusions upon 



NO. 1446. VOL. 56] 



the range of vertebrated animals only. A few manuals, 

 such as M. Trouessart's excellent book, and Mr. Beddard's 

 " Text-book of Zoogeography " in the Cambridge series 

 of scientific handbooks, have attempted a rather wider 

 survey of the facts of the science, the necessity for which 

 is emphasised by the short essay now before us. The 

 main object of the science of geographical distribution 

 is clearly, we take it, to state the facts ; but it is illogical 

 to avail oneself merely of a selected series of facts. This 

 is particularly evident in view of another aspect of the 

 science ; for some of its more important inferences 

 deal with the former changes in the relative position of 

 oceans and continents. Birds and mammals being com- 

 paratively modern creations, can throw no light upon 

 more distant changes of this kind ; and facts drawn from 

 those groups are by no means sufficient to serve as a 

 basis for the view, now so generally becoming accepted, 

 that there was in earlier times a vaster antarctic continent 

 than the shrunken remnant now exir.ting. Dr. StoU 

 strongly supports this notion, and it is from invertebrate 

 groups that arguments are to be drawn. He is, more- 

 over, against the theory of polar dispersal, which by its 

 ingenuity, if for no other reason, has commanded much 

 attention. Dr. StoU clearly shows the importance of a 

 consideration of invertebrates in discussing the in- 

 ferences of geographical distribution, and we could have 

 wished that his little brochure of only 113 pages had 

 been more expanded. 



Transactions of the American Microscopical Society. 

 Edited by the Secretary. Vol. xviii. Pp.413. (Buffalo, 

 N.Y. : A. T. Brown, 1896.) 



This report of the proceedings of the American Micro- 

 scopical Society at the nineteenth annual meeting, held at 

 Pittsburg in August of last year, is a very creditable pub- 

 lication. Many of the papers are distinctly valuable 

 contributions to science, and the plates which illustrate 

 them are of a high standard of excellence. Among the 

 subjects and authors are the following : — Notes on com- 

 parative histology of blood and muscle, by Miss Edith J. 

 Claypole ; the character of the epithelium of the peri- 

 toneum of the tailed amphibia of the Cayuga lake basin, 

 by Miss I. M. Green ; several interesting papers on 

 photomicrography, and on water supply ; the red blood 

 corpuscle in legal medicine, by Dr. M. C. White (accom- 

 panying this paper are some fine photo-engravings of 

 blood corpuscles of man and various animals, magnified 

 X 10,850,2560,840, and 640 diameters) ; yeasts and their 

 relation to malignant tumours, by Dr. A. R. Defendorf ; 

 the bacteriology of diphtheria, by Dr. C. F. Craig ; and 

 an instructive address by the President, Dr. h. Clifford 

 Mercer, on the effect of aperture as a factor in micro- 

 scopic vision. 



Experimental- Untersuchungen iiber Elektricitdt von 

 Michael Faraday. No. 86, Series iii. to v., pp. 103 ; 

 No. 87, Series vi. to viii., pp. 179. Edited by .A.. J. v. 

 Oettingen. (Leipzig: Wilhelm Engelmann, 1897.) 



These two volumes are the latest additions to Prof. 

 Ostwald's renowned " Klassiker der exakten Wissen- 

 schaften " — a series of edited translations and reprints 

 which has no rival. They contain translations of papers 

 read by Faraday before the Royal Society in 1833-4, 

 upon his electrical researches, the translations being from 

 the Philosophical Transactions of those years. A few 

 explanatory notes are added by the editor, Dr. .-\. J. v 

 Oettingen. 



Complaints are often made of the neglect of foreign 

 scientific literature by German investigators, but it 

 should be remembered at the same time that we have no 

 series of translations of scientific classics to compare 

 with the one in which the two present volumes appear. 



