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II. ADefcription of an Engine, to raife Water hy the 
Help of Quickplver^ invented hy the late 
Jofliaa Haskins, and improvd hy J. T. Defagu- 
liers, LL. D. R. S S. 
R. Hnskins finding that all Hydraulic Engines, 
working wirh Pumps, lofe a great deal of 
Water, falways giving Ids than the Number of Strokes 
ought to give according to the Contents of the Bar- 
rels;) and that when the Piftons are new leather’d to 
prevent that Lofs, the Friction is much increas’d, and 
the Engines are fubjed: to Jerks, which in great Works 
do often diforder an Engine for a great while, by 
breaking fome of the Parts ; contriv’d a new way of 
raifing Water without any Fridion of Solids; making 
ufe of Quickfilver inftead of Leather, to keep the 
Air or Water from (lipping by the Tides of the Pi* 
Rons in the Barrels where they work ; hoping there- 
by to prevent all the abovefaid Inconveniences, and 
alfo to have Water Engines lefs liable to be out 
of Order than any yet made. 
The firft Experiment he made with an Engine that 
he fet up at my Houfe about two Years ago, which 
1 repeated before the Royal Society in a Model ; and 
tho’, by the ill Contrivance of the Parcs, it did not 
raife near the Quantity of Water that the Invemioa 
is capable of ; yet 1 (hall defcribe the Machine here, 
becaufe it will fcrve for the better Underftanding of 
our prefent Engine. 
B 
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