May ii, 1882] 



NA TURE 



29 



creased the size of the work. This is somewhat to be 

 regretted, as they are matters of quite as much importance 

 as fixed oils, &c, to which a long chapter is devoted, and 

 their inclusion would have certainly increased the value of 

 the book for all general purposes. 



The chapters on paraffins, terpines, and homologues of 

 benzene are very clear, and in many cases detailed 

 methods of assay, as, for instance, with benzene, anthra- 

 cene, &c, are given that will be found of practical value. 

 A large chapter is devoted to the description of 

 methods of examination of fatty oils and fats employed 

 in the soap manufacture, and the same section also gives 

 considerable general information respecting varieties of 

 soap with methods in some cases improved by the 

 a uthor, for the analysis of soaps ; in particular a tabular 

 arrangement of analysis of a soap on p. 242. 



About 100 pages are devoted to the important subject 

 cT sugars, and in this space we find an admirable con- 

 densation of methods in use, both optical and chemical, 

 for the detection and determination of the various varie- 

 ties of sugars met with commercially. The optical por- 

 tion is prefaced by some short remarks on construction, 

 and varieties of polometers in use, which might with 

 advantage have been somewhat extended. 



All the methods given in this section are up to date, 

 and cannot fail to be of use not only to the practical man, 

 but to the student. 



The chapter on the alkaloids is also a very complete 

 compilation of methods of detection, &c, that have been 

 proposed and found to be reliable up to date. No doubt 

 the book will be found valuable as a reliable compilation 

 "f methods, 6cc, as such, saving much time and trouble 

 in referring to the original publications. The author is 

 an eminently practical chemist, and in his preface to the 

 first volume seems to deride the teaching of " ultimate 

 organic analysis" and the "ringing the changes on the 

 cverlasting-chloro-bromo and nitro derivatives of bodies 

 of the aromatic series." 



The quality of Mr. Allen's production atones somewhat 

 tor this ebullition, for his book requires a considerable 

 amount of theoretical knowledge to be possessed by the 

 user; and it is very desirable, if we are to maintain a 

 position as chemists at all, that the cant about "purely 

 practical work " should cease, and a more thorough foun- 

 dation in theoretical chemistry be imparted to students, 

 so that they may become reliable practical men, and not 

 mere machines for manipulating test-tubes. 



.Xordcnskjbld's Arctic Voyage Round Asia and Europe. 

 A Popular Account of the North-East Passage of the 

 Vega, 1878-80. By Lieut. A. Hovgaard. Translated 

 from the Danish by H. L. Braekstad. Maps and Illus- 

 trations. (London : Sampson Low and Co., 1882.) 

 Lieut. Hovgaard, of the Danish Navy, was one of the 

 most efficient members of Baron Nordenskjold's well- 

 selected staff on board the Vega. When he returned from 

 the remarkable voyage, he very naturally felt impelled to 

 tell his countrymen how he had fared and what he had 

 seen. This he has done in a pleasant and popular style, 

 utilising to some extent the material collected by his 

 chief. Lieut. Hovgaard, while dealing mainly with its 

 lighter aspects, gives a fairly complete sketch of the 

 voyage. The translation is well done, and the translator 

 deserves special credit for the intellgible way in which he 

 has rendered Russian names. The illustrations are not 

 up to a very high mark. 



The Sphygmographj its History and Use as an Aid to 

 Diagnosis in Ordinary Practice. By R. E. Dudgeon, 

 M.D. Svo., pp. 72. (London : Baillie're, Tyndall, and 

 Cox). 



This book may be of some service to beginners, as it 

 gives rudimentary instruction in the use of the instrument, 

 but this is all it does. The history is carelessly written, 



the account of the indications given by the sphygmo- 

 gram is imperfect, and the deductions drawn are some- 

 times, we think, incorrect. From a curve in the upstroke 

 the author concludes that the ventricular contraction is of 

 a peristaltic character, a conclusion which would be most 

 important if it were correct. But he does not at all take 

 into consideration the great probability that this curve is 

 due to instrumental error, inasmuch as it does not appear 

 in the tracings obtained by Marey's sphygmograph, in 

 which the connection of the writing-lever with the artery 

 is more perfect than in Dr. Dudgeon's instrument. The 

 chief value of the book consists in the description and 

 directions for applying Dr. Dudgeon's sphygmograph, 

 which certainly possesses the great advantage over other 

 instruments, that it is much cheaper, and can be applied 

 much more quickly, and with much less trouble. 



A Great Mathematical Question. By T. Wakelin, B.A. 



(Melbourne : G. Robertson, 1881.) 

 A pamphlet of 16 pp., with a coloured diagram, the 

 object of which is to show the fallacy of the measure of 

 kinetic energy. It is an account of the old dispute 

 originated by Leibnitz, and about seven pages are taken 

 up with extracts from Whewell's " History of the In- 

 ductive Sciences" (vol. ii. pp. 6S-70) ; Penny Cyclo- 

 paedia, "Vis Viva"; Encycl. Brit., "Energy"; Balfour 

 Stewart, "Heat" (pp. 301-4); and Routh's "Rigid 

 Dynamics" (pp. 260, 263, 270-1), with a reference to 

 Todhunter's "Mechanics" (pp. 210, 211). We would 

 suggest, as additional references, Clerk Maxwell, " Mat- 

 ter and Motion" (§ lxxvii.), and Tait's "Recent Ad- 

 vances in Physical Science." Mr. Wakelin concludes: 

 " It will therefore be seen that the distance through which 

 a body falls during the time of falling, is not a measure 

 of the work of the force of gravity during that time. 

 This, of course, means that the ordinary measure of the 

 kinetic energy of a mass in motion is an erroneous one." 



LETTERS TO THE EDITOR 



[The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications. 



[ The Editor urgently requests correspondents to keep their letters 

 as short as possible. The pressure on his space is so great 

 that it is impossible oth, rwist to ensure the appearance even 

 of communications containing interesting and neicl facts.\ 



The Existence of a Voice in Lizards 

 The letters on the existence of a voice in lizards, by M. 

 Fascoe and S. P. Oliver, in Nature, vol. xxv. pp. 32, 174, 

 gave me much pleasure, being a confirmation of observations 

 first made and published by myself in 1S74, but doubted in 

 different quarters. In my paper, " Zoologische Studien auf 

 Capri, II. Lacerta muralis coerulea, ein Eeitrag zur Darwinschen 

 Lehre, Leipzig, Engelinann, 1S74" (p. 20), I have laid down 

 the result of my observations, in the first instance, concerning 

 the habits of the bluish-black wall-lizard, Zacerta muralis 

 ctvrulea, discovered by me on the Faraglione rock near Capri, 

 and subsequently on those of other wall-lizards. There, I say : 

 " To the harmlessness (or fearlessness, mentioned previously) of 

 the blue inhabitant of rocks — Lacerta muralis carulca — I owe 

 the discovery of the animal's intonating capacity, a \ eculiarity 

 generally ascribed among reptiles to the geckoes and chamceleons, 

 but never observed in wall-lizards till now." 



One summer-day I heard in the room where I kept a cage of 

 lizards a peculiar sound, similar to the piping of a nestling, only 

 softer. Having listened attentively, I was surprised to find it 

 proceeding from the throat of one of my male blue lizards. 

 Leisurely resting on a stone, the animal repeated the sound 

 a dozen times, perhaps at intervals of about a quarter of a 

 minute, each time opening its mouth a little way. For several 

 consecutive weeks I noticed the same kind of voice in other 

 individuals of both sexes, after which period I did not hear 

 it for months. A series of these calls were taken down by 

 me from ear ; I give them here : " chri, bschi, ria, bi, bschia." 



