362, On Rain, Evaporation, Se. 
The following observations were made when 
the water passed through both pipes: that is» 
when the vessel was filled up with earth above 
the level of the upper pipe. 
Top pipe Bottom pipe. 
’ Inch. Inch. 
$796, Jan. 25—— ,190—— ,280 
30-—— ,o80—— 4114 
Feb, 2—— ,100-—— 5254 
8—— 3196-—— 214Q 
May 1—— ,163——~ ,000 
10—— ,060—— ,400 
12—— ,312——— 4175 
15—— ,190—— 200 
June 3—— 120 3040 
ee ee 
Total 1.411 
ee 
1.603 
The column of mean evaporation is derived 
by taking the difference of the two columns pre- 
ceding it; but it should be observed that though 
this method is sufficiently exact in taking the 
year together, it is not so in taking the 
months severally, because it presumes that the 
earth in the vessel contains the same quantity of 
water at the end of each month, or is saturated 
with it; whereas in the Summer months it is 
frequently short of saturation. The consequence 
is, that the evaporation appears from this table 
to be something less than it really is in the Sum; 
