SCIENCE-ADVERTISEMENTS 



Storage 



Batteries 



^'Chloride Accumulators" 



and 



"Exide Batteries" 



Are thoroughly satisfactory for scientific 

 work, which accounts for their being used in 

 so many of the educational and research 

 laboratories throughout the United States. 



If you are equipped, and after long service 

 your "Chloride" battery needs some re- 

 newals ; or if you contemplate a new instal- 

 lation we are ready to serve you. 



By arrangement with the factory we act as 

 Special College Representatives and are pre- 

 pared to furnish portable or stationary out- 

 fits, with any number of cells for current 

 capacity from | ampere to any maximum 

 desired. 



May we send you catalog ? To aid us in 

 rendering good service, please state what 

 your requirements are. 



JAMES G. BIDDLE 



121 1 ARCH STREET 

 PHILADELPHrA 



A one year's course for beginning students 



Theoretical Mechanics 



By J. H. JEANS 



The subjects dealt with are the general 

 principles of dynamics, the laws of 

 motion, statics, and dynamics of a par- 

 ticle and of rigid bodies. Emphasis is 

 placed primarily on the elucidation of 

 the fundamental physical principles 

 rather than on the elaboration of a 

 mathematical theory. Care has been 

 taken to illustrate all principles and re- 

 sults by a series of practical examples 

 and applications. The amount of 

 mathematics in the text has been re- 

 duced to the minimum. 



364 pages, illustrated with diagrams, 

 $3-00 



Ginn and Company 



Boston 

 New York 

 Chicago 

 London 



The University of California Press 



Berkeley, CaUfornls 280 Madison Avenue, New York 



SOME TESTS OF DOUGLAS FIR 

 AFTER LONG USE 



By Arthur C. Alvarez 70 



The Strength of Long-Seasoned [Douglas Fir and Red- 

 wood, by Arthur C. Alvarez 10 



Some Compressioii Tests of Portland Cement Mortara and 

 Concrete Containing Various Percentage of Silt, by 

 .Arthur C.Alvarez and.James R. Shields 25 



TheJ.Wintun Hesi Ceremony, by S. A. Barrett 50 



New Pacific Coast [Marine Algae III, by Nathaniel Lyon 



Gardner 35 



New Pacific Coast Marine Algae IV,, by Nathaniel Lyon 



Gardner 10 



The above titles represent University of California Publicationt 

 in Engineering, Anthropology and botany. Other series 

 pabllahed by the University of California include Agricultural 

 Sciences. Entomology, Geogiaphy, eology. Pathology, 

 Physiology Psychology, and Zoology. 



Complete Uste of titles and prices will lie tent 

 on reonest 



