Dec. 2 1, 1871] 



NATURE 



141 



OUR BOOK SHELF 



Marvels of Pond- Life: or a Year's Microscopic Recreations 

 nmon^ the Polyps, Infusoria, Rotifers, Water-Beats, 

 tind Polysoa. By Henry J. Slack, F.G.S., &c. Second 

 Edition. (London : Groombridge and Sons.) 

 This liule volume is already so well .ind favourably 

 known to microscopists that any formal notice or com- 

 mendation is scarcely necessary. Professing only to be a 

 first book on " Pond- Life," it does not attempt more than 

 to guide the young student in searching after, collecting, 

 and examining the various animal organisms which in- 

 habit fresh water. The division into months indicates 

 that it is also popular rather than abstruse, and the num- 

 ber of species mentioned or figured is very limited. There 

 appears to be no good reason why the present edition 

 should not have made an advance beyond its predecessor, 

 and given us an additional chapter or two on the con- 

 struction and management of small aquaria at home, 

 adapted especially and entirely to minute pond-life, by 

 means of which metropolitan students might continue 

 the study when unable to go to the ponds ; and also on 

 those artificial ponds for the evolution of Infusoria, so 

 much alluded to of late, infusions of organic substances. 

 Keeping in view the simple pretensions and elementary 

 character of this volume, it fully answers the design of its 

 author, and we are glad to announce the appearance of a 

 second edition. 



Physikalisches Repetitoriutn, &^c., &'C. Von Dr. Ferdi- 

 nand Bothe. Second Edition, revised and enlarged. 

 (Brunswick: Vieweg, iS/r.) 

 A BRIEF enumeration of the more prominent facts and 

 formula; of physics ; carefully divided into subjects, and 

 with occasional dates and names of inventors or disco- 

 verers. We conceive that to make an excellent work of 

 this kind (if such a thing be at all desirable), all that is 

 necessary, is to take a really good treatise on natural phi- 

 losophy and construct something between an Index to, 

 and an Abstract of, its contents. It seems probable 

 that some such process has been employed by Dr. Bothe ; 

 but eiiher he cannot have used a trustworthy book for 

 analysis, or his analysis is not a faithful one. In fact, if 

 we look on it seriously, a more painful volume we have not 

 often met with ; nor a more amusing one, if we could fancy 

 its blunders intended to amuse. We simply open its pages 

 at hazard, and make a few pickings : — 



" 64. The density and resilience {Spannkraft) increase 

 in proportion to the pressure, the \-olume is inversely as 

 the pressure, and vice <v';-j'(? — Boyle's or Mariotte's Law, 

 1679." James Bernoulli was a contemporary of these 

 men, and says in his work, " De Gravitate Aetheris," 

 " \'eritas utriusque hujus reguhv manifesta fit duobus 

 curiosis experimentis ab Illustr. Dn. Boylio banc in rem 

 factis, qua: videfis \sic\ in Tractatu ejus contra Linum." 

 The date of this tract of Boyle's is 1662, and it is to be 

 observed that Bernoulli does not mention Mariotte at 

 all. We notice, in pissing, that Young's name is not 

 mentioned under Capillarity, and we arrive at the follow- 

 ing curiosity : — " 140. Unit of momentum or of work 

 {Arbeit) is the force {Kraft) which can in one second 

 communicate to unit of weight a velocity of unit of 

 length. (Its) metrical measure is the kilogramme metre ; 

 in Prussia, England, &c., the foot-pound." But we beg 

 Dr. Bothe's pardon. We had no right to render Arbeit 

 by " work," which is its usual equivalent in scientific books ; 

 for looking back we find : — " i 29. The product of the 

 weight of a body into its velocity is called .Vlomen'um, 

 and also /i/Zw/" ! It is scarcely possible to conceive a 

 more hopeless jumble of essentially different thinjjs than 

 these sentences exhibit. The Heliotrope is (46S) ascribed 

 to Gauss, 1S30 (?}. Did not Drummond use it in 1S26.'' 

 471 gives Bunsen and Kirchhoff the credit of the spectro- 

 scope, with its collimator, &c. What of Swan ? As to the 



equality of absorption and radiation. Angstrom is given 

 without date, Stokes and Balfour Stewart not mentioned. 

 " 472. The planets and comets (I) send back only the rays 

 which the sun has sent to them." 4S4. In the enumera- 

 tion of the earliest attempts to produce photo.:;raphic im- 

 pressions, there is no mention of Wedgwood, &c. 558. 

 No mention is made of Northmore, whoie long priority in 

 the liquefaction of gases was insisted on by Faraday. 592. 

 The old story of Mayer and the dynamical theory of heat. 

 His date is given as 1 842 ; Davy and Rumford (who did all 

 that is referred to in the text more than forty years before) 

 are not mentioned. Joule is coupled with Clausius, and the 

 date iS53isassignedtothem ! Of Carnot, Colding, Rankine, 

 Thomson, &c., not a word. 59S-600. The experimental 

 laws of heat of combination are very imperfectly given, 

 and, without any mention of Andrews and Hess, handed 

 to Thotnsen and Favre and Silbermann, with the date 

 1853 ! 666. The similarity of the order of bodies con- 

 sidered separately as conductors of heat and electricity is 

 given to Wiedemann and Franz in the same proUfic year. 

 Surely Forbes pointed it out twenty years earlier ! So far 

 as we have seen. Sir W. Thomson, Clerk-Maxwell, &c , 

 are not even named in the book. 



If the reader remember that these are merely the things 

 which have caught our eye in turning over tlie pages at 

 random, he will not blame us for absolutely declining to 

 examine the work more closely. A series of working 

 tables is appended, but without very close examination we 

 should hesitate to trust them, after what we have seen of 

 the character of the book. That we have noticed it at all 

 is due to the circumstance that some consolation is to be 

 derived from the mere fact of its existence. We are all 

 (in consequence, perhaps, of recent events) more or less 

 imbued with the notion that Germany (Prussia especially) 

 is rapidly taking the lead in matters of scientific education 

 and investigation ; and no doubt there is some truth in 

 this. But the game is not lost, we are not yet passed in 

 the race, and our old supremacy is quite within our reach 

 even now, provided we make speedy and sufficient exer- 

 tions to regain and maintain it. It will not drop into our 

 mouths for a mere wish ; but is it reasonable to wonder at 

 the state of science in this country, where so few states- 

 men pay the least attention to it, when we find that even 

 in enlightened Prussia, such a book as the above can be 

 written by a recognised teacher, and published in a second 

 edition by one of the highest firms in the world? 



LETTERS TO THE EDITOR 



[ The Editor docs not hold himself responsible for opinions expressed 

 by his correspondents. No notice is taken of anonymous 

 comnninications. ] 



Proof of Napier's Rules 



I AM greatly obliged to "J. J. W. " for pointing out the objec- 

 tion of a want of generality in the construction of the figure con- 

 tained in my former letter (in Naturk, No. 106), for the proof 

 of Napier's Rules; which the more general construction no^r 

 described by "J.J. W." most simply anJ most effectually re- 

 moves. To illustrate his more perfect general construction with 

 a figure — D is the centre, and B12B' a part of the circumference 

 of a circular piece of cardboard, upon which the arcs Bi, 12 are 

 taken equal to the sides of the right-angled splierical triangle 

 which it is required to represent. If we jum DB, Dt, D2, and 

 draw BC, CA perpendicular to Dl, D2, the lalter perpen- 

 dicular prolonged meeting the circle of the circumference in B', 

 and join DB' ; and on AB' as diameter describe the semicircle 

 AC'B' ; and with the centre K, and radius AC, another circle, 

 meeting the semicircle in C, so that the straight line AC is equal 

 to AC ; and join B'C. Then it is easily shown that if AC CB 

 are the two sides, AB' is the hypothenuse of a right-angled 

 triangle, which, when the four triangles are closed together so as 

 to form a solid figure, will coincide with the triangle AC'B'. As 

 BC {or B'C) will then be perpendicular both to CD and to CA 

 (or C'A), it will be perpendicular to the plane DCA ; and the 



