[ 18 ] 
iy pa 1 
Experiments on Evaporation, and Meteorological Obferva- 
tions made at Bradford in New-England, in 1772, by 
the Rev. SAMUEL WILLIAMS, A. M 
N making experiments on the quantity of water that 
evaporated in the year 1771, the method I ufed, was 
to fill the veffel the beginning of every month: In the 
_courfe of thefe experiments, I obferved that in the begin- 
ning of the month when the tube was newly filled, it ex- 
hauited much fafter than towards the latter end, when one 
or two inches of the water was evaporated; and that the 
quantity of evaporation meafured this way, came out lefs 
than the quantity of rain that fell in the courfe of the 
year. The beginning of the year 1772, I attempted to 
examine this matter more carefully. With this view I 
made the following experiments. 
EX POR NL EON WT. 
I procured two cylindrical veffels of three inches diame- 
ter, and fix deep, as much alike as they could be made: 
One, I filled with water as I had done in 1771, once a 
month; the other, with the fame kind of water, once a 
week; and placed them about fix inches apart, in fuch a 
manner as to be expofed to the wind, and fun, but cover- 
ed from the rain. The refult was, that which was filled once 
a week, exhaufted about one third more than the other. In 
Fanuary and February, the difference was a little lefs; in 
March and April, it was a little more. In May, the laft 
month in which I compared them, the evaporation from 
the former was 6.35 inches; from the other 4.10. By this 
experiment 
