Wisconsin State Agricultural Society. 
117 
wood absorbs more moisture, and holds it with greater tenacity 
than hard wood, because it is more porous and hence offers a great¬ 
er amount of surface upon which the moisture is condensed. 
The relation of soils to moisture is analogous to that of the 
sponge. A soil in good condition for the growth of plants con¬ 
tains no water as such. The greatest pressure may be applied 
without obtaining from it a single drop of water. Yet the soil is 
not dry. Condensed upon the surface of every particle of which it 
is composed, is a small quantity of moisture, and the composition 
of the soil being the same, the amount of this moisture will be in 
direct proportion to the surface exposed and upon which condensa¬ 
tion can take place. 
On this account, he who would take every precaution to furnish 
his growing crops with sufficient moisture, and secure them against 
the evil effects of draught, will cultivate his soil well, that it may 
hold within its pores that moisture which is readily given to the 
growing plant, although held there with great tenacity. 
Again, during our hot summers, an immense quantity of water 
is evaporated from the surface of soils exposed directly to the sun’s 
rays, as are our corn-fields. Or, if covered with a growing crop, 
the moisture is absorbed by the plants, and through them . passes 
into the atmosphere. In either case there is a great demand upon 
the soil for water, while perhaps for weeks no rain will fall. Water 
must be had by the crop or it fails at the harvest. 
But where is the supply to be obtained after that within the 
immediate reach of the roots is exhausted? 
s 
Every one is familiar with the experiment illustrating capillary 
attraction, in which water rises much higher in a small tube than in 
a large one, or perhaps the wick of a lamp drawing oil from the 
reservoir below is more familiar. The oil is drawn up through the 
minute channels existing in the wick, but unless the fibres of 
which it is composed are quite close together, and the channels 
very minute, the oil would not rise to supply the flame. 
Soils possess this same capillary power, and if loose and suffi¬ 
ciently fine, water will be brought from the deeper soil to supply 
this evaporation from the surface. But if the surface soil is coarse, 
and the deeper soil hard and compact, if they have not both been 
well broken up and pulverized by thorough cultivation, they are un- 
