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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL, 54 



above. Gray gives two set? of measurements, one made with large and 

 the other with small metallic plates : 



The lack of sharp concordance in these data and the consequently 

 high probable errors seem to indicate a distinct superiority of the purely 

 chemical method of determination over that adopted by the physicist. 

 This supposition is strengthened by the electrochemical experiments of 

 Eichards, Collins and Heimrod/ who precipitated copper and silver 

 simultaneously in the same current of electricity. Their first series, with 

 vacuum weights, is as follows : 



1 Proc. Amer. Acad., 35, 123. 1809. 



