SCIENCE—ADVERTISEMENTS 



Just out 

 KOFOID AND SWEZY 



The Free-Living 



Unarmored Dinoflagellata 



S62 quarto pages; 12 colored plates and 388 



figures in text. Paper, $12.50. 



Carriage extra, weight 7 lbs. 



A monumental work on these elusive organisms, 

 based on years of observation off the coast of Cal- 

 ifornia, in the Eastern Tropical Pacific, and in the 

 plankton traverse of the Northern and Western 

 Pacific and Indian oceans. 



The work sets forth a summary of present know- 

 ledge, makes clear the causes of discolored seas 

 and phosphorescence of ocean waters, and offers 

 new conceptions of the relationships of general 

 within the group. 



The University of California Press 



Berkeley, California 



19 Ea>t 47th Street, New York 



The Economics of Everyday 



Demand practical and funda- 

 mental training. It is of the 

 utmost importance that the high 

 school pupil should have an in- 

 terest in economic problems. 



Elementary Economics 



By Thomas Nixon Carver 



Gives a thorough training in the 

 groundwork of economics. It is 

 written especially for high schools 

 in plain, understandable language. 

 Interesting, non-technical, com- 

 plete. 



GINN AND COMPANY 



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NEW WILEY BOOKS editions 



JUST ISSUED 



Laboratory Manual in General Microbiology 



Second Edition. Prepared by the Laboratory of Bacteriology and Hygiene, 

 Michigan Agricultural College, WARD GILTNER, Head of Department. 



This book prepares the student for specialization in any field of bacteriology 

 — it is adapted to use in colleges and universities in any course of study. 

 472 pages. 5j by 7f. 79 figures. Cloth, $3.50 postpaid. 



Ready September 1 — Second Edition Revised 



Elementary Chemical Microscopy 



By EMILE MONNIN CHAMOT, B.S., Ph.D., 



Professor of Sanitary Chemistry and Toxicology , Cornell University 

 A revised, up-to-date edition of this standard textbook, which outlines the 

 manipulation of the microscope and shows how it serves to shorten the work 

 of the chemical analyst and renders more accurate results. 



Enter your order for Free Examination copies — " GILT NER" now," CHA- 

 MOT" when ready. 



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