2206. Pumps are of various kinds; as the lifting pump; the forcing pump, for very deep wells; the suction pump; and Siebe's rotatory pump, for shallow wells which do not exceed 33 ft. in depth. A good pump for gardens, where the water is not to be raised above 28 ft. or 30 ft. in depth, is that of Robertson Buchanan (author of a Treatise on Heating by Steam, &c.), because this pump, which also acts by the pressure of the atmosphere, will raise drainings of dunghills, or even water thickened by mud, sand, or gravel. Shalder's pump is another of the same kind. Aust's (of Hoxton) curvilinear pump is preferable even to Buchanan's. The advantages depend on the curvilinear form of the barrel, which allows, and indeed obliges, the rod, the handle, and the lever, on which it works, to be all in one piece. Hence simplicity, cheapness, precision of action, more water discharged in proportion to the diameter of the barrel, and less frequent repairs. (Repertory of Arts, Jan. 1821.) Perkins's square-barrelled pump is a powerful engine (London Journal, &c.); but for this and other contrivances for raising water we must refer to works on hydraulics.
