LOW LIFT PUMPING MACHINERY. LXIXx. 
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rotary pump in which he found that it only raised 57% of the 
displacement of the piston. 
The efficiency of these pumps is low as will be seen from 
Figure 1, the highest shewn there being 547%. Some tests made 
on a rotary pump working against a head of 129’ shew the follow- 
ing results :— 
Gallons per hour. Efficiency. 
8-00 
27120 63°30 
32160 59°20 
