fTuNE 2, 1916] 



SCIENCE 



781 



$10 per 1,000 quoted by one firm for medium 

 weight and $14 per 1,000 for heavy weight 

 driers. When it is considered that a large part 

 of the material pressed imder the old system, 

 using blotters alone, required the use of two 

 blotters between each specimen, it will be seen 

 that a considerable saving is effected in the 

 cost of the drying material as well as in the 

 time required to handle and completely dry the 

 material. P. L. Eicker 



Bureau op Plant Industry 



a new color variety of the norway rat 



ISToRWAY rats with dilute coat color have re- 

 cently been taken in the vicinity of the Uni- 

 versity of Pennsylvania. If we may judge 

 from the fact that the nine individuals thus 

 far found are all approximately alike and are 

 distinctly diilerent from the normal type, they 

 probably represent a new Mendelian variety. 



The coat is intermediate in color between 

 that of the ordinary dark form and the albino 

 and resembles that of the red-eyed guinea pig. 

 In the guinea pig this color has been shown 

 by Wright to be allelomorphic with albinism 

 and with dilute. As in the guinea pig, the hair 

 of the new rat seems to be without yellow pig- 

 ment and is dilute black or brown ticked with 

 white. 



The eyes look black ixnless the light is very 

 bright. When the light shines directly into 

 them they appear pink. They are distinctly 

 lighter than the eyes of Castle's red-eyed yellow 

 rats, but darker than those of his pink-eyed 

 yellows. 



The new rats are now in the care of the 

 Wistar Institute, where the endeavor is being 

 made to increase the stock and to cross with 

 the color varieties already known. 



Data in regard to the distribution of the new 

 form is being collected and will later be pub- 

 lished. 



The previously known Mendelian varieties 

 in the rat are five: black, hooded, albino and 

 Castle's two yellow varieties, red-eye and pink- 

 eye. This new variety is a non-yellow dilute 

 and may be called ruby-eye. 



Phineas W. Whiting 

 XJniversitt of Pennsylvania 



SYLVESTER AND CAYLEY 



Under the portrait with which the editor 

 has adorned my article " Sylvester at Hop- 

 kins," in The Johns Hopkins Alumni Maga- 

 zine of March, 1916, the designation is simply 

 " James Sylvester." 



This omits his real name, his family name, 

 the name to which he was bom ; for his father 

 was Mr. Abraham Joseph, his two sisters 

 were the Misses Joseph. The name by which 

 we know him he chose for himself, following 

 the example of his eldest brother, who early 

 in life established himself in America and 

 assumed the name of Sylvester. 



My laborious and critical friend. Professor 

 G. A. Miller, of the University of Illinois, in 

 his recent book " An Introduction to Mathe- 

 matical Literature," commits the colossal 

 error of representing Sylvester and Cayley as 

 friends together at college, Cambridge chums, 

 whereas Sylvester entered Cambridge in 1831 

 and Cayley was senior wrangler at Cambridge 

 in 1842, more than a decade later. Sylvester 

 had already in the" session 1837-38 been ap- 

 pointed professor in London University Col- 

 lege, and it was in London, but only after the 

 lapse of nearly another decade, in fact in 1846, 

 that Cayley met Sylvester. 



George Bruce Halsted 



Greeley, Colo. 



SCIENTIFIC BOOKS 



Indian Mathematics. By G. E. Kaye. Cal- 

 cutta & Simla, Thacker Spink & Co., 1915. 

 Pp. 73. 



Of all the British writers on the history of 

 Indian mathematics at the present time, none 

 is better known or more serious in his purpose 

 than Mr. Kaye. A scholar by nature and, 

 through his connection with the Indian serv- 

 ice, placed in an environment which is con- 

 ducive to the study of the original sources, few 

 men have the opportunities which are his for 

 bringing the mathematical learning of the 

 East to the knowledge of the West. 



This being the case, the reader might nat- 

 urally expect to find in a publication with 

 such a title as this an exhaustive and well- 



