On Rain, Evaporation, €c. 359 
€vaporation for 4 years was—January 1.50 
inches.—February 1.77.—March 2.64.—April 
3-30-—May 4.34.—June 4.41.—July. 5.11. 
—August 5.01.—September _ 3.18.—October 
2.51—November 1.51.—December 1.49.— 
In all 36.78 inches. The mean rain for the 
same time was 37.48 inches.—In the year 1793 
I found the evaporation from water in a similar 
way at Kendal for- 82 days in March, April, 
May and June to be 5.414 inches, The greatest 
quantity evaporated on one of the hottest and 
driest days in Summer was a little above ,2 of 
an inch in depth, 
The experiments to determine how much is 
évaporated from green ground and from moist 
earth, are very few that have come to my know- 
ledge. Dr. Hales, from a few experiments, 
calculates that’ moist earth only throws off 62 
inches annually.—This calculation must be far 
below the truth. Dr. Watson, Bishop of Llan- 
daff, found that in a dry season there evaporated 
from a grass plat that had been mowed clese, 
about i600 gallons in an acre per day, which 
amounts nearly to ,o7 of aninch in depth; and that 
after rain the evaporation was considerably more. 
Now supposing ,07 to be the medium daily eva- 
poration for May, June; July and August, and 
that as much is raised in these 4 months as in 
all the rest of the year, the annual evaporation 
F 
