Patent for a new and improved pump. This design "has been specially devised for use in pumping gas, air, or vapor — as in ice-machines, for instance — and mainly with reference to attaining circulation with low pressure; but when operated at high speed considerable pressure may be attained therewith, whether operating upon vapors or liquids, as . . . [the] pump involves a novel mode of operation, in that it possesses characteristics partially common to pumps of the rotary system, as well as to those having a reciprocating piston" (lines 10-21).