The work is commenced by opening a short piece of ditch by hand, and strings of pipes, each about 50 feet long, are added as the work proceeds; and when the ditch is completed, the rope is withdrawn. When the surface is uneven, the uniform slope is preserved by means of a wheel and screw, which governs the plug, or coulter, raising or lowering it at pleasure. A man upon the frame-work controls this wheel, guided by a sight on the frame, and a cross-staff at the end of the field. Drains, 40 rods long, are finished at one operation. This plow has been carefully tested in England. Its work has been uncovered when completed, and found perfect in every respect. The great expense of the machine, and the fact that it is only adapted to clay land free from obstructions, has prevented its general use. We cannot help believing that, by the aid of steam, on our prairies, at least, some such machine may be found practicable and economical. PRATT'S DITCH DIGGER, Patented by Pratt & Bro., of Canandaigua, is attracting much attention. We have not seen it in operation, nor have we seen statements which satisfy us that it is just what is demanded. It is stated, in the _Country Gentleman_, to be incapable of cutting a ditch more than two and a half feet deep. A machine that will do so much is not to be despised; but more than one half the digging remains of a four-foot ditch, after two and a half feet are opened, and we want an implement to do the lowest and worst half. It is stated that, in one instance, a ditch, 60 rods long, about two feet deep, in hard clay, was cut with this machine, worked by two horses, in five hours. We trust that the enterprising inventors will perfect their implement, so that it will open drains four feet deep, and thus meet the great want of the public. It is not to be expected that any such implement can be made to operate in ground full of stones and roots; and inventors should not be discouraged by the continual croakings of those sinister birds, which see nothing but obstacles, and prophecy only failure. [Illustration: Fig. 89.--PRATT'S DITCH DIGGER.] The drain plow was first introduced into Scotland by M'Ewan. The soil in his district was mostly a strong unctuous clay, free from stones. He constructed an immense plow, worked by 12 or 16 horses, by means of which a furrow-slice, 16 inches in depth, was turned out; and, by a modification of the plow, a second slice was removed, to the depth, in all, of two feet. This plow is expensive and heavy, and incapable of working to sufficient depth. Mr. Paul, of Norfolk Co., England, has lately invented an ingenious machine for cutting drains, of which we give an elevation. [Illustration: Fig. 90.--PAUL'S DITCHING MACHINE.]