[ 288 ] ' 



inch, of which I have given the ratio, and have converted 

 Reaumur's into Fahrenheit's fcale. It appears that between 54^,5 

 and 99", 5 evaporation is nearly proportional to the differences of 

 the temperature of the water, for as 22,5 (the difference between 

 54'', 5 and 77") is to 3, fo 45, (the difference between 54", 5 and 

 99^,5) is to 6. 



From a feries of experiments which I profecuted in London 

 during the year 1785, I am inclined to think that, other circum- 

 ftances being equal, the ratios of evaporation to the temperature of 

 water, are as expreffed in the following table : 



These experiments were made on water contained in a cylin- 

 drical glafs veffel, under a furface of 25,23 fquare inches, and 

 containing 23,13 cubic inches. It was partially expofed to the 

 wind and air between the hours of twelve and two o'clock in the 

 afternoon, but fheltered from rain. In winter the initial heat of 

 the water was generally a few degrees higher than that of the 



air. 



