On Evaporation. . 3893 
porable.—I have lately made several observa- 
tions on this subject, the results of which, as far 
as they go, support the conclusion that the ge- 
neral law of evaporation continues the same 
below the point of congelation as above it. All 
the experiments were made in the tin vessel 
above described of 6 inches in diameter; a 
quantity of water was suffered to freeze in it, so 
as to form a circular cake of ice; the vessel 
and ice were then weighed together, and exposed 
in the open air fora certain time, after which 
being again weighed, the loss was found; the 
force of the aqueous atmosphere was sometimes 
determined during the experiment by a mixture 
“of pounded ice and salt, in the manner already 
described, 
Crs. H. Gre, Wind. Air. 
Nov. 5.In the night lost 110 in 9 ; or, .20 perm. N.E. brisk. 28° to 31° 
—— atl0 A.M. — 25in 12;o0r,.33 —— N.E. mod. 32° 
—29.at 1 P.M. — 24in 14; or, .23 —— calm. 31° 
P.M. — 84in 92; or, .15 —— 30° 
——30. in the night —- 94in 9 ; or,.17 —— N.E.mod. 31° 
Dec.19. P.M. — 75in 8 ;0r,.16 —— N.E.caim, 26o-—28° 
Inthe night— 33in11 ;o0r,.05 —— calm, 4 Q9° 
—20. A.M.— 21in 2 ;o0r,.175 —— W. mod, Sie 
Some of these being made in the night, and 
of long duration, neither the temperature of the 
air, nor the force of the aqueous atmosphere 
could be fairly determined: the second experi~ 
ment was made under every favourable circum. 
