We have few soils that may not be trenched with the plow or spade to any depth that is attainable. And here let me explain what is meant by _trenching_: it is the transposition of two layers of the soil more thoroughly, and to a greater depth, than is done by simply digging or plowing, in which a limited amount, only a thin layer of the soil, is inverted. In trenching with the spade, a narrow strip of land is excavated across one end of the piece to be trenched, eighteen or twenty inches wide, and as deep as the spade can take it out at two diggings. The earth thus removed is thrown aside, to be used at the end of the work. The trench being now open, a similar space is laid off, and the surface soil, to the depth of the spade, is dug and thrown into the bottom of the first trench, after which the subsoil is dug to the same depth, the length of the space, and thrown on top of the surface soil that was put into the bottom of the first trench. A second trench is thus opened, and a third strip being then marked off, the same processes are continued, until the whole piece is trenched, when the pile of earth first excavated is brought into requisition to complete the work, by filling up the last trench. This is common trenching, which reverses the two layers of soil, and stirs the whole to the depth of eighteen or twenty inches. It is an expensive operation, but very desirable in a small fruit-garden--not at all applicable for extensive orchard planting, though often applied to the preparation of extensive vineyards. Trench plowing is conducted upon the same principle, and is done by using two plows in the same furrow, the first taking off the surface soil and throwing it into the deep furrow of the second plow, which is so constructed as to lift the lower soil and throw it high up over the furrow slice laid by the first, and at the same time, leaving a deep furrow open behind it to receive the next cut of surface soil. The two layers are thus inverted and reversed at the same time, and with a proper plow, the whole soil is finely comminuted and reduced to a perfect seed-bed, suitable for a garden. To perform this work, the Double Michigan plow is the favorite implement. It should be properly constructed, for much depends upon having the plow well made; the mold-boards should be formed upon the best models for their respective offices of reversing the surface soil, and of upheaving and comminuting that which lies below it; and these mold-boards should be made of steel. Such plows are manufactured at several points, but all the Double Michigan patterns are not equally good, and some are quite unsatisfactory.