SMITHSONIAN 



CONTRIBUTIONS TO KNOWLEDGE 



VOL. XXI, 





EVEKY MAN 13 A VALUABLE MEMBER OF SOCIETY, WHO, BY HIS OBSERVATIONS, RESEARCHES, AND EXPERIMENTS, PROCnRES 



KNOWLEDGE FOR MEN. SmITHSON. 



CITY OF WASHINGTON: 

 PUBLISHED BY THE SMITHSONIAN INSTITUTION. 



MDCCCLXXVI. 



