human
or surface drains about twenty inches deep and twenty inches wide at top, narrowing to six inches at the bottom. This process may be called
gpt
which begins to shrink visibly. The puffy rounded surface gradually sinks as the water runs off, and the earth gains in solidity. When this process is sufficiently advanced the drains are cleared and deepened, and a wedge-shaped sod, too wide to reach the bottom, is rammed in so as to leave below it a permanent tubular covered drain, which is thus made without tiles or other costly material. Then the surface is dressed with lime, which, as the people say,