Horse-power of a pump. Is the same as is used to designate that of a steam engine, with this exception: the initial pressure in the pump remains constant throughout the stroke. Formula is the same as for a steam engine.

Hump.” This is an arch or bend which causes an “air pocket” in a water-pipe line.

Hydrant. A valve and spout connecting with a street main.

Hydraulic Belt. An endless woolen band for raising water. The lower bight is immersed in water, and the upper bight passes over a roller. The belt travels about 1,000 feet per minute, and discharges at its upper turn.

Hydraulic Jack.

Hydraulic Jack. A lifting device in which a ram, a pump, and liquid is used instead of a screw.

Hydraulic Pivot. A “slippery liquid support” for an upright shaft, a film of water being introduced beneath it by pressure to support the weight thereof and prevent the usual friction of the shaft on its step.

Hydraulic Shears. A machine for shearing or cutting metals, etc., by the force of water pressure operating cutters.