SCIENCE— ADVERTISEMENTS 



NEW BOOKS 



KEW 

 Cretaceous and Cenozoic Echinoidea 

 of the Pacific Coast 



133 Pages, 40 Plates, Paper $2.50 



SWARTH 

 Revision of the Avian Genus 

 Passerella 



149 Pages Paper $1.75 



ALLEN 

 Plankton of the San Joaquin 

 River 



292 Pages Paper $3.00 



Carriage Extra 



The University of California Press 



Berkeley, California 19 Eait 47tli Street, New York 



Internal = Combustion 

 Engines 



By Wallace L. Llnd, U. S. N. 



Embodies the very latest information 

 upon the subject. All important 

 types of motors, including airplane 

 and automobile motors, are dis- 

 cussed and illustrated. 

 Of special interest and practical 

 value is the chapter on ' 'Troubles, ' ' 

 which deals with both causes and 

 remedies. 



For engineering courses and schools 

 for aviators and automobile operat- 

 ors. 



QINN AND COMPANY 

 70 Fifth Ave. New York 



ANNOUNCING 



"The New Physics" 



By DR. A. C. CREHORE 



Author of "The Mystery of Matter," 

 "The Atom," Etc. 



This is an incisive analysis of recent re- 

 search in physics. It develops simplified 

 expressions for all electrical units in terms 

 of length and time, showing specific 'induc- 

 tive capacity and magnetic permeability to 

 be the reciprocals of a velocity and consider- 

 ing electronic mass as a function function of 

 velocity. It includes discussion of the gravi- 

 tational equation and of electro magnetic 

 theory based upon the generalized Minkowski 

 space, thus leading to new and valuable 

 concepts. 



128 pp., 4 j^ X 6. Price, S2.00 postpaid 



A Book Every Physicist Should Own 



Published November, 1920, by 



Journal of Electricity 



Rialto Bldg., San Francisco 



THE 

 BAHAMA FLORA 



BY 



Nathaniel Lord Britton 



Director-ln-Cblef of the New York Botanical Garden 

 AND 



Charles Frederick Millspaugh 



Curator of Botany in the Field Museum of 

 Natural History 



An octavo volume of 695 pages 

 Published by the authors 



Copies may be obtained from 



Mr. G. K. Ackerman 



Lorillard Mansion 



Bronx Park New York City 



Price $6.S5, which includes postage 



