January 6, 1898] 



NATURE 



219 



growing need of a good practical and elementary course 

 on sound. The present work admirably supplies this 

 need, and constitutes a worthy companion to the well- 

 known volumes already published in the Stewart and Gee 

 series. The author is, moreover, thoroughly familiar 

 with the experimental side of his subject ; besides being 

 clearly and concisely written, his work is thus rendered 

 very interesting to read. 



Starting with chapters on the nature of sound and 

 wave motion, he discusses in the following order the 

 sonometer, resonance, determination of frequency, rods 

 and plates, tuning forks, pipes, harmonic motion, reflec- 

 tion and refraction of sound, velocity of sound, Doppler's 

 principle, musical scale, analysis of sounds, interference, 

 beats, differential and summational tones, «S:c. The book 

 ends with a useful list of workers in theoretical and 

 experimental acoustics, with dates of birth and death. 



Sound is a subject which lends itself to pretty experi- 

 ments, and there is no lack of such here. To choose 

 one instance out of many, we may refer to Expt. xc, in 

 which the refraction of air waves in the Sondhauss 

 exf)eriment is imitated in water by making ripples pass 

 over a shallow circular patch in a deeper sheet of water, 

 and thus retarding them as the air-waves are retarded 

 by the C0.> 



More might perhaps be made of the india-rdbber cord 

 as an illustration of the properties of stretched strings. 

 By causing a metronome to beat at the same rate as a 

 horizontally stretched cord, it is easy to obtain good 

 quantitative results, while the slowness of the vibrations 

 is a great help to unimaginative students in subsequently 

 understanding the behaviour of stretched wires. 



There is a mistake in the diagram on p. 22, where, 

 of the two quantities plotted, one should be replaced 

 by its reciprocal if the result is to be a straight line. 

 On p. 105 there is a 2 omitted from the equation for /. 



These are, however, trifling slips in a work for which 

 teachers of physics cannot fail to be grateful to the 

 author. A. P. C. 



AMERICAN GAME BIRDS. 

 The Gallinaceous Game Birds of North A/nerica. By 

 D. G. Elliot. 8vo, pp. xviii + 220, illustrated. 

 (London : Suckling and Co., 1897.) 



THE author of this little volume is already so well 

 known to naturalists from his splendid illustrated 

 folio monographs of various groups of mammals and 

 birds, that any work from his pen needs but little in the 

 way of commendation. Among his monographs are two 

 respectively devoted to the grouse and pheasants, and it 

 is the American representatives of these groups that he 

 now describes in a less elaborate form, and with the 

 advantage of all the observations recorded since the pub- 

 lication of his larger works. The present volume is 

 indeed the companion to the author's " North American 

 Shore Birds," which has already been well received ; and 

 since a large number of British sportsmen now visit the 

 States, the demand for the work ought to be considerable. 

 Although not so good as some we have seen, the photo- 

 gravures with which the work is illustrated are for the 

 most part of a fair grade of excellence, and afford every 

 facility for the identification of any specimen with which 

 the naturalist or sportsman may meet. 

 NO 147 1, VOL 57] 



The work commences with a general dissertation on 

 game birds and their affinities, written in such a popular, 

 and at the same time such exact, style, that it should prove 

 acceptable to readers of every class. Following this is a 

 description of the habits and characteristics of the various 

 North American representatives of the group, which, in- 

 clusive of subspecies, total up to forty-four. A feature of 

 the work is that the main portion of the text devoted to 

 each form is headed solely by the popular name of the 

 particular species or race ; the technical name and de- 

 tailed description com.ing at the end of each section. In 

 view of the general shuffling of scientific names now 

 taking place in all classes of animals, their relegation 

 to a subordinate position in a popular work is by no 

 means inadvisable ; and those readers who so desire, 

 can easily skip the technical portions altogether. 



Apart from these technical descriptions, the work is 

 written in a bright and attractive manner, the habits of 

 the different species being noted in considerable detail, 

 and their geographical distribution most carefully worked 

 out. It will be a matter of satisfaction to many to learn 

 that while certain kinds of game birds are dying out 

 from the effects of persecution in the more settled 

 districts, some others are gradually making their way 

 to the wilder districts of the west, where they will meet 

 with better chances of survival, t 



As mar^' of our readers are aware, with the exception 

 of the grouse and ptarmigan, which have a circumpolar 

 distribution, the game birds of North America are totally 

 distinct from those of the Old World ; the pheasants, 

 quails, and partridges of the latter being quite unknown 

 in the former area, where their place is taken by the 

 so-called American partridges. The author might have 

 explained that this difference is doubtless due to the 

 inability of either of these groups to withstand the cold 

 of high northern latitudes which apparently prevailed at 

 the time of a land bridge 7'id Bering Strait. A parallel 

 instance is afforded by the absence of hyienas and 

 civets from America. 



As regards classification, the author departs con- 

 siderably from the view usually adopted in Europe. 

 Instead of restricting the TetraonidcB to the grouse and 

 ptarmigan, he includes in that family the Old World 

 Perdicina and the American Odontophorina:, both of > 

 which are usually placed in the Phasianidce. Apart 

 from all other considerations, the circumpolar distribu- 

 tion of the grouse and ptarmigan renders it in the 

 highest degree desirable that they should be kept as the 

 sole representatives of a family differing by its distribution 

 from all the other groups of the order. 



A series of coloured papers illustrating the colour- 

 terms employed in the text concludes this well-written 

 and useful compendium of North American game birds. 



R. L. 



OUR BOOK SHELF. 

 LEclairage iVAcHylHe. Par G. Pellissier. Pp.237. 



(Paris : Carre et Naud, 1897.) 

 In England the discovery of calcic carbide, and the 

 ease with which acetylene may be prepared from it, has 

 attracted a large amount of attention ; but the literature 

 of the subject is practically restricted to a few papers 

 read before various societies and to the returns of the 



