ical CEble: 



FOR DETERMIMXG THE 



ELASTIC FORCE OF AQUEOUS VAPOR 



RELATIVE HUMIDITY OF THE ATMOSPHERE 



INDICATIONS OF THE WET AND THE DRY-BULB THERMOMETER 



FAHRENHEIT. 



BY 



JAMES H. COFFIN, A.M. 



PROFESSOR OF MATHEMATICS AND NATURAL PHIDOSOPHY, IN LA FAYETTE COLLEGE, 

 EASTON, PENNSYLVANIA. 



WASHINGTON: 

 PUBLISHED BY THE SMITHSONIAN INSTITUTION. 



1856. 



