Mine Suction Pump of Bored Logs: Perforated Trunk, Valve Box and Leather-Shoe Piston (Agricola, 1556)

"Thus the workman, eager at his labour, standing on the flooring boards, pushes the piston down into the pipe and draws it out again."

Bore straight logs through their length to make the pipe, first with a borer with an auger and then with a wider borer (Illustration 177, O-Q). Use one length, or two with one joined into the other.

Make a trunk two feet deep, hollow like the pipe, its lower opening blocked with a round piece of wood and its sides perforated round about so water flows in. Make a box of iron, copper or brass one palm deep, without a bottom, closed by a rounded valve that stops the raised water running back. Set it in the top of the trunk if there is one pipe, or in the lower pipe at the joint if there are two.

Lay a flooring over the sump. Let the pipe down through it to the bottom of the sump with the trunk on its lower end, and fix it with pointed iron clamps driven in straight on both sides. Cut an opening or spout in the upper pipe reaching to the drain of the tunnel.

Fit the piston rod with a hand-bar at the top. At the bottom fix either a shoe, a leather covering stitched almost cone-shaped, tight round the rod and wide open at the top, or (far better) a disc of iron one digit thick or of wood six digits thick, fixed by an iron key through the rod or screwed on, with five or six round or oval openings in a star and a cover over them, the same diameter as the inside of the pipe.

Standing on the flooring, push the piston down and draw it up. On the up-stroke the cover closes the disc openings and the water above is lifted to the spout, while the valve of the box opens and water from the trunk rises by suction; on the down-stroke the valve closes and the water passes up through the disc.

From Georgius Agricola, **De Re Metallica** (1556), Book VI, translated by Herbert C. and Lou H. Hoover, 1912 (Gutenberg 38015; checked on the archive.org scan georgiusagricola00agri, pp. 176-177). He gives no bore, pipe length or lift. The metric equivalents of his Roman units, the suction limit and the tools are ours.