October 13, 1898J 



NATURE 



567 



the thermometer. Here, however, there is no such 

 nonsense. 



The third book of this part deals with thermo- 

 dynamics, and we must enter our protest once more 

 against the mode of treatment adopted for absolute 

 temperature. As is usual in German and French 

 treatises temperature is first defined by the so-called 

 law of gases, and then based on the hypothetical some- 

 thing called a perfect gas. Then that notion of temper- 

 ature is carried into the discussion of the indicator 

 diagrams given by Carnot's engine. Of course if a 

 perfect gas is properly and clearly defined the discussion 

 can be made logically consistent, though in what seems 

 a forced and unnatural way ; and Prof. Riecke is careful 

 to state, though not quite all at one place, what the 

 properties of his perfect gas are. 



The true method is to define absolute temperature by 

 means of a perfect engine, so as to get a scale indepen- 

 dent of the properties of any known substance, and then 

 Joule and Thomson's experiment becomes a comparison 

 of the scales of different gas thermometers with the 

 absolute scale, that is a test of the perfection of the 

 gases. So far as we have been able to see, the name of 

 Thomson is not mentioned in this section of the work ! 



In taking leave of this treatise we wish to say that 

 students owe much to Prof. Riecke for giving them a 

 readable, not too abstruse, and yet thoroughly sound 

 and fairly full discussion of the elements of physics. To 

 many German students who have not time to struggle 

 through the larger treatises this book must be very 

 welcome. A. Gray. 



A NEW DEPARTURE BY THE RAY 

 SOCIETY. 

 The Tailless Batrachians of Europe. Part II. By G. 

 A. Boulenger, F.R.S. (London : The Ray Society, 

 1898.) 



WE recently reviewed under the above heading the 

 first part of the above-mentioned work, which 

 will become classical among popular treatises upon 

 zoology, and the second part, following so close upon 

 it, calls for nought but the highest admiration. In the 

 131 pages which compose its body, the Bufonidas, 

 Hylida;, and Ranidae, are treated in a manner uniform 

 with the contents of the first volume, with which it 

 is serially paged. There are 14 plates, of which 10 

 are coloured, 4 maps, and 44 text illustrations, all 

 of the same excellence as in the first part ; and the 

 whole work well-nigh challenges criticism, it being 

 praise sufficient to remark that it is its author's. 

 Although the pages deal professedly with European 

 animals, their value is materially enhanced by the 

 recognition of the world-wide distribution of these, 

 with especial reference to local varieties — as, for ex- 

 ample, the Japanese and Chinese Bufones. The difficult 

 topic of the racial varie^ties of the Ranidaj is for the 

 first time handled in popular terms, the author giving 

 the results of his ripe experience in a concise tabular 

 form which will be of the greatest use to both the way- 

 side and professed naturalist. Nor is the experimental 

 aspect of the study neglected, and concerning this, in 

 his disproof of the Fischer-Sigwart hypothesis (p. 311), 

 NO. 151 I, VOL. 58] 



the author once again displays a commendable enthu- 

 siasm and love of science for its own sake which cannot 

 fail to exercise the healthiest influence upon the reader's 

 mind. Equally encouraging is his frequent allusion to 

 the work of the dillettanti, not a few among his critical 

 observations and records as to geographical distribution 

 and breeding period being culled from the pages of 

 journals and the publications of local Natural History 

 Societies, which the too academic critic might be apt to 

 ignore. Under this head the incorporation of observ- 

 ations like those of Mr. Norman Douglass is deserving 

 especial comment, as furnishing encouragement to the 

 mere lover of nature and those content to seek our 

 familiar creatures in localities in which they are un- 

 known, and as bringing to these persons a full assurance 

 that their efforts do not pass unnoticed by the leading 

 masters of their craft. To the popular mind, the record 

 of a toad's attempt to swallow a viper, and of the edible 

 frog's more regular habit of snake capture, will especially 

 appeal, as an interesting fact concerning the balance of 

 nature. 



The book concludes with an appendix of 16 pages ; a 

 bibliographical index of 13 pages ; and an alphabetical 

 index to the two parts. The appendix embraces a list of 

 the specimens preserved in our National Museum at 

 South Kensington, and to peruse this is to realise that 

 the work is a popular commentary upon a collection un- 

 paralleled by that of any other museum in the world — a 

 glorious possession of the British race. With this at his 

 command the author could not have achieved other than 

 a great result, but still by no means the least conspicuous 

 feature about it is the stamp of his own individuality and 

 personal influence which it bears. His book is worthy 

 this unique material, and the best endeavours of all con- 

 cerned in its accumulation ; and while congratulating the 

 Ray Society upon the success of their new departure, 

 we earnestly hope that its executive will forthwith 

 consider the advisability of making corresponding and 

 ample provision for a companion work on the Batrachia 

 Caudata, regarding that as at present the object most 

 deserving their support, and most worthy their old- 

 established reputation as pioneers in the popularisation 

 of biology. 



There are a few trivial matters of terminology in the 

 present volume, such as the usage of the words " hand," 

 '* sternum," and "anus," and one or two expressions of 

 orientation, to which exception might be taken ; but 

 these are altogether trivial where all else has been so 

 nobly done. 



OUR BOOK SHELF. 



Morality independent of Obligation or Sanction. By 



M. Guyau. Translated from the French (second 



edition) by Gertrude Kapteyn. Pp. xii -f- 215. 



(London : Watts and Co., 1898.) 



In the twilight of gods and systems has naturalism any 



word as to the conduct of life? The author of "The 



Irreligion of the Future" feels that the scientific spirit in 



its revolt can rest in no optimism theological or teleo- 



logical, while, discounting pessimism of temperament as 



simply the symptom of unfitness of life, the pessimism 



put forward as a general solution can be shown to be 



bound up with psychological illusion and is negatived by 



