Cable: 



FOR DETERMINING THE 



ELASTIC FORCE OF AQUEOUS YAPOR 



AND THE 



RELATIVE HUMIDITY OF THE ATMOSPHERE 



FROM 



INDICATIONS OF THE WET AND THE DRY-BULB THERMOMETER 



FAHRENHEIT. 



BY 



JAMES H. COFFIN, A.M. 



PROFESSOR OP MATHEMATICS AND NATURAL PHILOSOPHY, IN LA FAYETTE COLLEGE, 

 EASTON, PENNSYLVANIA. 



WASHINGTON: 



PUBLISHED BY THE SMITHSONIAN INSTITUTION. 

 1856. 



