Bottoming Tools.—The only tools which are wanted of peculiar form in draining, are such as are used in forming the narrow part of the trenches at the bottom. We can get down two feet, or even three, with the common spade and pick-axe, and in most kinds of drainage, except with tiles, it is necessary to have the bottom as wide, at least, as a spade. In tile-draining, the narrower the trench the better, and in laying cylindrical pipes without collars, the bottom of the drain should exactly fit the pipes, to hold them in line.
Although round pipes are generally used in England, we have known none used in America until the past season—the sole-pipe taking their place. As the sole-pipe has a flat bottom, a different tool is required to finish its resting-place, from that adapted to the round pipe. As we have not, however, arrived quite at the bottom, we will return to the tools for removing the last foot of earth.
And first, we give from Morton, the Birmingham spades referred to by Mr. Denton, in his letter, quoted in this chapter. They are the theoretically perfect tools for removing the last eighteen or twenty inches of soil in a four or five-foot drain. Mr. Gisborne says of the drain properly formed:
"It is wrought in the shape of a wedge, brought in the bottom to the narrowest limit which will admit the collar, by tools admirably adapted to that purpose. The foot of the operator is never within twenty inches of the floor of the drain; his tools are made of iron, plated on steel, and never lose their sharpness, even when worn to the stumps; because, as the softer material, the iron, wears away, the sharp steel edge is always prominent."
Fig. 70.
Fig. 71.
Fig. 72.