The first work is the opening of the ditches to a depth of about 3 feet, which may be best done with the common spade, pick, and shovel, except that in ground which is tolerably free from stones, a subsoil plow will often take the place of the pick, with much saving of labor. It _may_ be drawn by oxen working in a long yoke, which will allow them to walk one on each side of the ditch, but this is dangerous, as they are liable to disturb the stakes, (especially the grade stakes,) and to break down the edges of the ditches. The best plan is to use a small subsoil plow, drawn by a single horse, or strong mule, trained to walk in the ditch. The beast will soon learn to accommodate himself to his narrow quarters, and will work easily in a ditch 2-1/2 feet deep, having a width of less than afoot at the bottom; of course there must be a way provided for him to come out at each end. Deeper than this there is no economy in using horse power, and even for this depth it will be necessary to use a plow having only one stilt. [Illustration: Fig. 25 - FINISHING SPADE.] Fig. 25 - FINISHING SPADE. Before the main line is cut into the open brook, this should be furnished with a wooden trough, which will carry the water across it, so that the ditch shall receive only the filtration from the ground. Those laterals west of the main line, which are crossed by the brook, had better not be opened at present,—not until the water of the spring is admitted to and removed by the drain. [Illustration: Fig. 26 - FINISHING SCOOP.] Fig. 26 - FINISHING SCOOP. The other laterals and the whole of the main line, having been cut to a depth of 3 feet, take a finishing spade, (Fig. 25,) which is only 4 inches wide at its point, and dig to within 2 or 3 inches of the depth marked on the stakes, making the bottom tolerably smooth, with the aid of the finishing scoop, (Fig. 26,) and giving it as regular an inclination as can be obtained by the eye alone. [Illustration: Fig. 27 - BRACING THE SIDES IN SOFT LAND.] Fig. 27 - BRACING THE SIDES IN SOFT LAND. If the ground is "rotten," and the banks of the ditches incline to cave in, as is often the case in passing wet places, the earth which is thrown out in digging must be thrown back sufficiently far from the edge to prevent its weight from increasing the tendency; and the sides of the ditch may be supported by bits of board braced apart as is shown in Fig. 27. [Illustration: Fig. 28 - MEASURING STAFF.] Fig. 28 - MEASURING STAFF. The manner of opening the ditches, which is described above, for the main _A_ and its laterals, will apply to the drains of the whole field and to all similar work.