Alderman Mechi, of Tiptree Hall, says: "Filtration may be too sudden, as is well enough shown by our hot sands and gravels; but I apprehend no one will ever fear rendering strong clays too porous and manageable. The object of draining is to impart to such soils the mellowness and dark color of self drained, rich and friable soil. That perfect drainage and cultivation will do this, is a well known fact. I know it in the case of my own garden. How it does so I am not chemist enough to explain in detail; but it is evident the effect is produced by the fibers of the growing crop intersecting every particle of the soil, which they never could do before draining; these, with their excretions, decompose on removal of the crop, and are acted on by the alternating air and water, which also decompose and change, in a degree, the inorganic substances of the soil. Thereby drained land, which was, before, impervious to air and water, and consequently unavailable to air and roots, to worms, or to vegetable or animal life, becomes, by drainage, populated by both, and is a great chemical laboratory, as our own atmosphere is subject to all the changes produced by animated nature." Experience proves that the descent of water through the soil renders it more porous, so that it is easier for the water falling afterward to pass down to the drains, but no very satisfactory reason for this has been presented, beyond that which is connected with the cracking of the soil. The fact is well stated in the following extract from a letter to the _Country Gentleman_: "A simple experiment will convince any farmer that the best means of permanently deepening and mellowing the soil is by thorough drainage, to afford a ready exit for all surplus moisture. Let him take in spring, while wet, a quantity of his hardest soil,—such as it is almost impossible to plow in summer,—such as presents a baked and brick-like character under the influence of drought,—and place it in a box or barrel, open at the bottom, and frequently during the season let him saturate it with water. He will find it gradually becoming more and more porous and friable,—holding water less and less perfectly as the experiment proceeds, and in the end it will attain a state best suited to the growth of plants from its deep and mellow character."