Many plumbers prefer lead pipe, so that they can make the usual plumbers’ joint. The tail _m_ of the pump is for fixing the suction pipe on a plank level with the ground. Stages _n_ are fixed at every 12 ft. in a well; the suction pipe is fixed to these by a strap staple, or the action of the pump would damage the joints. There are two plans for fixing the suction pipe; (1) in a well _o_ directly under the pump; (2) the suction pipe _p_ may be laid in a horizontal direction, and about 18 in. deep under the ground (to keep the water from freezing in winter) for almost any distance to a pond, the only consideration being the extra labour of exhausting so much air. In the end of such suction pipe _p_ it is usual to fix an extra valve, called a “tail” valve, to prevent the water from running out of the pipe when not in use. The action is simply explained. First raise the handle _e_, which lowers the piston _b_ to _i_; during this movement the air that was in the barrel _a_ is forced through the valve in the piston _b_; when the handle is lowered, and the piston begins to rise, this valve closes and pumps out the air; in the meantime the air expands in the suction pipe _k_, and rises into the barrel _b_ through the valve _i_; at the second stroke of the piston this valve closes and prevents the air getting back to the suction pipe, which is pumped out as before. After a few strokes of the pump handle, the air in the suction pipe is nearly drawn out, creating what is called a vacuum, and then as the water is pressed by the outward air equal to 15 lb. on the sq. in., the water rises into the barrel as fast as the piston rises: also the water will remain in the suction pipe as long as the piston and valves are in proper working order. The following table of dimensions for hand-worked simple lift-pumps will be found useful:-- +-----------+-------------+---------------+--------+------------+ |Height for | |Water delivered|Diam. of|Thickness of| |Water to be| Diam. of | per Hour at |Suction | Well Rods | | raised. |Pump Barrel. |30 Strokes per | Pipe. | for Deep | | | | Min. | | Wells. | +-----------+-------------+---------------+--------+------------+ | ft. | in. | gal. | in. | in. | | 14 | 6 | 1640 | 4 | 1 | | 20 | 5 | 1110 | 3 | 1 | | 30 | 4 | 732 | 2½ | ⅞ | | 40 | 3½ | 555 | 2½ | ¾ | | 50 | 3 | 412 | 2 | ¾ | | 75 | 2½ | 260 | 2 | ⅝ | | 100 | 2 | 183 | 1½ | ⅝ | +-----------+-------------+---------------+--------+------------+ [Illustration: 7. Lift and Force Pump. 8. Deep-well Pump.]