Mat 19, 1916] 



SCIENCE 



713 



two to three inches beneath the surface. Jack 

 rabbits inhabited the areas in great numbers 

 and it was first observed that wherever alka- 

 line waters had come in contact with their 

 feces the water, which usually held in small 

 puddles, took on a dark brown color not unlike 

 that of the waters holding in many unclean 

 barnyards after a rainstorm. The decom- 

 position of the fecal matter appeared to be 

 comparatively rapid when in contact with the 

 alkaline waters or with the moist alkali soil 

 and air. The animal refuse was observed in 

 all stages of decomposition from the fresh 

 droppings to the complete disappearance of 

 the original organic material. With the eva- 

 poration of the waters which had been in con- 

 tact with this refuse the soil took on the brown 

 color noted and responded to tests for nitrates. 

 Fecal matter from cattle and horses was later 

 observed undergoing the same type of decom- 

 position and producing similar brown spots 

 containing nitrates. All of the water on the 

 playas examined was of an alkaline nature. 



Since these observations are in harmony 

 with the established principles of niter forma- 

 tion in India there was no hesitation in con- 

 cluding that the brown " niter spots " of the 

 playas were, as far as examined, of animal 

 origin. 



From these iN'evada observations it is safe 

 to predict that in fields of the arid western 

 states brown " niter spots " will appear when 

 live stock is pastured in the same and alka- 

 line waters are used for irrigation. In this 

 connection it would be important to know if 

 live stock was pastured in the fields in which 

 Stewart and Peterson made their observations. 

 This fact would seemingly have an impor- 

 tant bearing on their conclusions. 



"Walter Stalder 



San Francisco, Calif. 



SCIENTIFIC BOOKS 



Historical Introduction to Mathematical Liter- 

 ature. By G. A. Miller, Professor of 

 Mathematics in the University of Illinois. 

 New York, The Macmillan Co., 1916. Pp. 

 xiii -f 302. 

 This valuable work is decidedly imique. It 



is not a history of mathematics, yet contains 

 much accurate historical information. It is 

 not a bibliogTaphy of mathematics, yet it says 

 much about books, journals and dictionaries. 

 It is not a volume on mathematical recrea- 

 tions, yet is most interesting reading. It is 

 not a philosophy of mathematics, though it 

 illumines such matters as Betrand Russell's 

 definition of mathematics as " the subject in 

 which we never know what we are talking 

 about nor whether what we are saying is true." 

 It is not a collection of biographies, though 

 brief sketches of twenty-five leading mathe- 

 maticians are given in one of the chapters. 

 The book gives much miscellaneous informa- 

 tion on recent mathematical activity in differ- 

 ent countries of the world. The organization 

 of mathematical societies, the starting of 

 mathematical journals, the trend of modern 

 thought along the lines of arithmetic, algebra, 

 geometry and analysis, are all presented in a 

 popular and pleasing manner, by one who is 

 able to take a broad view of the mathematics 

 of to-day. Attention is given to topics of 

 general interest, such as Format's last theorem, 

 magic squares, systems of numeral notation, 

 women mathematicians, the international com- 

 mission on the teaching of mathematics. The 

 purposes of the book, as expressed in the words 

 of the author, are "to meet the needs of a 

 text-book for synoptic and inspirational 

 courses which can be followed successfully by 

 those who have not had extensive mathe- 

 matical training. It may also be used as a 

 text-book for a first course in the history of 

 mathematics, especially by those teachers who 

 believe with its author that such a first course 

 should largely concern itself with recent 

 mathematical events and developments." This 

 aim is achieved in an eminently satisfactory 

 manner. The book meets a real want. 



The list of books on the history and the 

 teaching of mathematics, recommended by the 

 author, is selected more particularly to meet 

 the needs of English readers. This list makes 

 it painfully conspicuous that there are at pres- 

 ent no up-to-date general histories of mathe- 

 matics in the English language. The best gen- 

 eral histories are in the German language. In 



