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SCIENCE 



A. WEEKLY JOURNAL OF SCIENTIFIC PROGRESS 



Vol. II, No. 51, June 18, 1881. 



CONTENTS. 



Adulteration of Sugar (Edit.) ; The Metric System (Edit.) ; Sir William Herschell (Edit.) ; The Unity of Nature, by the 

 Duke of Argyll ; Meteorological Electricity ; The Aperture of Microscope-Objectives ; The Discovery of the Pre- 

 glacial Outlet of the Basin of Lake Erie, by Professor J. W. Spencer ; Books Received ; Faure's Secondary Battery ; 

 Microscopy ; The Stereorachys ; Letter from Professor John J. Mason ; Notes on Sun Spots, by Professor S. New- 

 comb, U. S. N.; General Notes, &c, &c, &c. 



Subscription, Four Dollars a Year. 



Single Numbers, Ten Cents. 



