SCIENCE. 



iii 



JUST READY. 



Illusions : 



A PSYCHOLOGICAL STUDY. By James Sully, author of 'Sensation and 

 Intuition,' 'Pessimism,' etc. International Scientific Series. i2mo, cloth, 

 price $1.50. 



" The present volume takes a wide survey of the field of error, embracing in its view not only the illusions of 

 sense, dealt with in treaties on psychological optics, etc., but also other errors familiarly known as illusions, and 

 resembling the former in their structure and mode of origin." — From Preface. 



" This is not a technical work, but one of wide popular interest, in the principles and results of which every one 

 is concerned. The illusions of perception of the senses and of dreams are first considered, and then the author 

 passes to the illusions of introspection, errors of insight, illusions of memory, and illusions of belief. The work is a 

 noteworthy contribution to the original progress of thought, and may be relied upon as representing the present 

 state of knowledge on the important subject to which it is devoted." — Popular Science Monthly. 



" Mr. Sully's analysis of his whole subject leaves us at the close impressed with the ability of the writer's 

 statement. — Saturday Review. 



For sale by all booksellers, or sent by mail, post-paid, on receipt of price. 



D. APPLE TON & CO., Publishers, 1, 3, and 5 Bond Street, New York. 



JAMES W. QUEEN & CO. 

 OPTICIANS, 



924 Chestnut St., Philadelphia, Pa. 



The New $50 Microscope 



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Write for Catalogue of Magnifying 

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Catalogues in 4 parts as follows : 

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SCIENCE 



A WEEKLY JOURNAL OF SCIENTIFIC PROGRESS. 



Vol. II, No. 59, 



August 13, 1 881 



CONTENTS. 



American Association for the Advancement of Science (Edit.); Astronomical Observa- 

 tories, by Simon Newcomb ; Michigan Flora, by Chas. F. Wheeler and Erwin F. 

 Smith; Disruption of Planetary Masses from the Primal Nebuln, by Edgar L. 

 Larkin ; Microscopical Technology, by Dr. Carl Seiler ; The Dearborn Observa- 

 tory (Annual Repoit); Observations on Comet (b), 1881, by W. C. W.; Weekly 

 Meteorological Reports for the City of New York, by Dr. Daniel Draper, Ph. D. 



WEBSTER. 



The following from Webster, page 1164, shows 

 the value of the Illustrative Definitions in 



Webster's Unabridged Dictionary 



Subscription, Four Dollars a Year. 



Single Numbers, Ten Cents. 



1, flying jib; 2, jib; 3, fore-top-mast-stay sail; 

 4, fore-course; 5, foretop sail; 6, foretop-gallant 

 sail; 7, fore-royal ; 8, fore sky-sail; 9, fore-roy- 

 al studding sail; 10, foretop-gallant studding- 

 sail; 11, foretop-mast studding-sail; 12, main- 

 course; 13, maintopsail; 14, maintop-gallant 

 sail; 15, main-royal; 16, main sky-sail; 17, 

 main royal studding-sail; 18, main top-gallant 

 studding-sail; 19, maintop-mast studding sail; 

 20, mizzen-course; 21, mizzen-top sail; 22, 

 mizzen-top-gallant sail; 23, mizzen-royal ; 24, 

 mizzen sky-sail; 25, mizzen-spanker. 



The pictures in Webster under the 12 words, 

 Beef, Boiler, Castle, Column, Eye, Horse, 

 Moldings, Phrenology, Ravelin, Ships, 

 (pages 1164 and 1219) Steam engine, Tim- 

 bers, define 343 words and terms far better 

 than they could be defined in words. 



New Edition of WEBSTER, has 

 118,000 Words, 3000 Engravings, 

 4600 New Words and Meanings, 



Biographical Dictionary 



of over 9700 Names. ? 



Published by G.&C.MERRIAM,Springfield,Ma£b 



