LOW LIFT PUMPING MACHINERY. LXxXxI. 
the bottom and top of the delivery barrel being trumpet-mouthed 
so that no water would be lifted an unnecessary inch and no con- 
traction of the vein take place at the bottom. In all pumps there 
are losses from—(a) The friction of the machinery ; (6) The friction 
of the water. In reciprocating pumps there is the further loss due 
to—(c) The loss of inertia from alteration of motion as the chambers 
fill and empty, which is absent in centrifugal and rotary pumps. 
And in low-lift pumps—(d) The needless height to which the water 
may be lifted. Now, with a large vertical barrel and a continuous 
stream of water delivered at a trumpet-head, the losses from (c) 
and (d) would be absent altogether, (b) would be reduced to a 
- minimum, and only the question of (a) is open. This point offers 
a very wide scope for inventive talent to devise a motive power 
that would ensure one bucket or piston always being in motion 
at its normal velocity and on the up stroke ; another piston would 
be commencing its ascent at normal speed before the other 
slackened in speed or commenced the return stroke downward. 
Without doubt 90% efficiency could be got if this principle was 
well worked out. 
Mr. GrimsHaw considered that little could be added to this 
extremely useful paper. He agreed with Mr. Selfe that improve- 
ment in the design of the scoop wheel by feathering the scoops 
Should very materially increase’ its efficiency for very low lifts. 
If, as the author states, the efficiency of the centrifugal pump for 
a lift of 30’ was greater than the reciprocating pumps, then by 
arranging these pumps at different levels the same efficiency might 
be obtained for a greater lift. If, for example, the efficiency was 
65% for 30’ lift, it would with two pumps at different levels give 
the same. At the same time the complication of pumps on 
different levels would not always be economical. He had an 
Opportunity of seeing a Liedler pump at work in Rotterdam and 
was much impressed with the advantage resulting from the high 
Speed it is enabled to run through the valves being mechanically 
controlled instead of left to take care of themselves as in the 
as ordinary pump. One of the great advantages of direct-acting 
6—July 21, 1897, 
