jYo, IL 



A DISSERTATION 



ON THE PRODUCTION OF VAPOR ; 



In which it is attempted to explain some curious pheno- 

 mena that attend its ascent. 



BY ELIZUR WRIGHT, ESQ. 



WATER has, till lately, been considered by phi- 

 losophers as an imcompoimded substance ; and 

 has accordingly been classed among the elements. Some 

 of the phenomena of water, on this principle, have been 

 of inexplicable solution. How it could come to pass, 

 that so ponderous a body as water should be raised and 

 sustained in the lighter air in the form of vapor, was 

 long viewed as a mystery. The fruitful imagination of 

 philosophers has, however, invented several hypotheses 

 to account for this wonderful process of nature. It has 

 been considered, that the gravity of bodies diminishes, 

 cseteris paribus, in proportion as the cubes of their diam- 

 eters, that is, as their solid content ; but their resistance 

 in a fluid, or their capacity of being supported by it, di- 

 minishes only as the squares of their diameters, that is, 

 as their surfaces. Hence, since the gravity decreases in 

 a higher ratio than the resistance, by diminishing the 

 bulk of any heavy body, it may be made to swim in a 



