144 _ AGRICULTURAL REDON. 
crease in the same ratio. Clay lands, either wet or dry, are the most 
difficult to work; sandy soils, and those containing much humus, are 
the most easy. . 
3. The firmness and consistency of a soil are not in the direct degree 
of its power of containing water; thus, fine lime and magnesia and 
humus possess but little consistency, although they can contain much 
water.’ We cannot, therefore, infer the existence of the one property 
from that of the other. 
4, Consistency generally exceeds in clayey soils, but not invariably. 
Fine, slaty marl, notwithstanding its great proportion of clay, has but 
slight consistence. The finest kind of pipe-clay in its dry state is only 
forty-two, and therefore less by half than that of the heavy, gray clay of 
arable soils. 
5. Light, sandy soils gain cohesive power by moisture; therefore, a 
damp climate, with a large average quantity of rain, will be found most 
advantageous to sandy districts. Even the purest sand, which in its 
dry state loses all its consistence and falls into a shapeless powder, re- 
gains a certain degree of cohesiveness on again being wetted. 
6. With all the earths, adhesion to wood exceeds that to iron; and the 
apparent contradiction of the fact that, in wet weather land is more 
easily worked with wooden than with iron implements, is explained not 
by the less degree of adhesion to wood, but by the weight of the iron 
implements causing them to sink deeper into the soil. 
Diminution of the consistency of soil by the penetration of frost.—After 
the thorough freezing of soil in a wet state, its degree of consistence is 
greatly decreased. This is especially the case with clays and soils of 
great firmness, where the diminution amounts to nearly one-half; with 
loamy clay the reduction reaches from sixty-nine to forty-five, and with 
ordinary arable soil from thirty-three to twenty. Completely dry earths 
suffer no change from the action of frost. This is because -the crystalli- 
zation of the waiter in the interstices of the soil by freezing forces the 
several particles of earth from their position, and thus renders the 
points of contact fewer. The beneficial influence of breaking up the 
soil before winter sets in, to allow the frost to penetrate more readily, 
depends upop this diminution of consistency. Lf the soil is worked in 
too wet a state in early spring the beneficial results are lost by again 
bringing the earthy particles into close contact. The throwing out of 
plants in changeable winters is caused by the alternate freezing and 
thawing of the ground, and the accompanying displacement of earthy 
particles forcing the roots of smaller plants out of the earth, but not 
displacing the larger ones. 
Capability of soils to become speedily dry.—It is a question of consider- 
able importance in vegetation whether a soil gives up its acquired 
moisture again to the air quickly, or retains possession of it for a long 
time in its force. 
1. The terms of a hot or cold, a dry or wet, soil rest chiefly on this 
capacity. Sand, gypsum, and slaty marl dry most quickly, and are 
consequently called hot soils. 
2. Carbonate of lime varies in this respect according to the different 
forms in which it occurs. Calcareous sand dries quickly, and fine car- 
bonate of lime slowly. The latter has, besides its chemical action on 
hamus, the advantage of loosening the soil after it is dried. 
3. This property of the earths, to require a longer or shorter time to 
become dry, might seem to stand in the same relation as their power of 
containing water, and, with thin layers, this is nearly always the case; 
but with layers some inches in depth the proportion deviates consider- 
