944 



SCIENCE 



[N. S. Vol. XXXIX. No. 1017 



States during recent years, that story awaits 

 another narrator; but, if only a desire, on the 

 part of Americans to learn more concerning 

 the place which American chemists occupy in 

 the world's history of chemistry, is awakened, 

 this compilation of facts will not only have 

 been a pleasure but it will have served a worthy 

 purpose." 



The book is to be regarded as a " compila- 

 tion" and not as a history. All American 

 chemists should be thankful to the author for 

 the pains he has taken to coUect this material 

 and for placing it before us. It furnishes the 

 basis for the history of chemistry in America 

 which remains to be written. 



It is interesting to note the fact that so 

 many of those who are necessarily mentioned 

 in the book were connected with the Univer- 

 sity of Pennsylvania. It is, therefore, most 

 appropriate that this work of compilation and 

 comment should have been done by the one 

 who at present holds tlie two important posi- 

 tions in that university of provost and pro- 

 fessor of chemistry. 



Iea Eemsen 



Das Belativitdtsprinzip. By Lorentz, Ein- 

 stein and Minkowski. Leipzig : B. Q. Teub- 

 ner. 1913. Pp. 89. 



Under the general title Portsehritte der 

 mathematischen Wissenschaften in Mono- 

 graphien, Otto Blumenthal is issuing a series 

 of which number 2 is a collection of six papers 

 by eminent advancers of mathematical physics 

 dealing with relativity. 



The first paper is a short note by Lorentz of 

 date 1895 in which the hypothesis of shorten- 

 ing in the direction of motion is discussed, 

 practically for the first time, though both he 

 and FitzGerald had for some time been famil- 

 iar with it. The second is a translation of 

 Lorentz's very famous Electromagnetic phe- 

 nomena in a system moving with any velocity 

 smaller than that of light, dated 1904. Here 

 not only the hypothesis of shortening, but the 

 Lorentz group, fundamental in relativity 

 theory, is found. 



The third article is Einstein's epochal for- 

 mulation (1905) of the principle of relativity 



as a fundamental physical principle indepen- 

 dent of any hypothesis of shortening. He 

 goes right at the heart of the matter in that 

 direct way which has been so characteristic 

 of his theories. The next is a short note, not 

 two and one half pages, in which Einstein 

 points out that a consequence of the foregoing 

 work is the proportionality of mass and 

 energy. 



Minkowski's Eaum and Zeit (1908) is the 

 fifth article. Here the-simple four-dimensional 

 formulation of mechanics and of the inverse 

 square law of attraction is first clearly ex- 

 hibited — yet not so clearly that Sommerfeld's 

 explanatory notes are unwelcome. This ad- 

 dress of Minkowski's had been reprinted sepa- 

 rately, and to the exhaustion of the edition is 

 perhaps due the publication of the present 

 collection. 



The final article is from Lorentz's Alte und 

 Neue Frage der Physik (1910) and forms an 

 appropriate close to a series which presents 

 concisely and at first hand the steps in the 

 development from the Michelson experiment 

 to the full fiedged theory of relativity. 



E. B. Wilson 



Controlled Natural Selection and Value Marh- 

 ing. By J. C. Notteam. New York, Long- 

 mans, Green and Co. 1914. Octavo. Pp. 

 130. 



The author of this book advances a new 

 theory to account for the origin of sexual di- 

 morphism and of polymorphism within animal 

 species. He starts with the assumption that 

 the competition in the struggle for existence 

 is frequently between groups rather than be- 

 tween individuals. Thus, family may com- 

 pete with family, or pair with pair, rather 

 than individual with individual. Conspicu- 

 ousness on the part of one member of the 

 family (its least necessary member) it is sup- 

 posed, may insure persistence of the family by 

 drawing the attacks of enemies to the one and 

 thus diverting them from the more valuable 

 members of the family. Thus male con- 

 spicuousness, in sexually dimorphic species, is 

 supposed to be advantageous to the female and 

 young. " Controlled natural selection ac- 



