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In six cases of different kinds of soils, the least 
difference between the two columns is 13° (in 
ealcarious sand) ; and the greatest difference is 13.95° 
(in garden earth, blackish gray). Taking the mean 
of summer temperature, this difference is equal to a 
removal from the latitude of Massachusetts to that of 
South Carolina. The benefit of this increase in tem- 
perature is felt in the spring, by bringing the land 
into good condition to work two or three weeks ear- 
lier; and also in the fall, by keeping off the frost two 
or three weeks later. Crops may be planted earlier, 
will have, on account of the higher temperature, a 
more vigorous growth during the summer, and will 
have ample time to mature in the fall before they 
can be injured by frost. 
Drains are peculiarly suited to our climate. 
The objection is often made that, though draining 
has been proved to be indispensable in Great Britain, 
yet here, on account of our drier climate, it is less 
needed. This is a false view of the subject. In 
England the fall, in a single day, of one inch vertical 
depth of rain is considered remarkable ; while here 
the fall of three or four inches is not uncommon, and 
a fall of nearly seven inches has been measured. We 
need, then, provision for carrying away four times as 
much surplus water as is provided for in England. 
Beside this, the humidity of the English climate is 
such that the evaporation is only about half what it 
is here. We have seen how heat is lost by evapo- 
