7 °

Hydraulics.

There is another Sort of Engine fofraising Water, which works by Fire, M

the

.which stood over it, and consequently could not haV >stll’d the Ve'ssel before the Water was driven in ; whichyet we find it did, and maintain’d an Equilibrium withthe common Air. The Vessel then being half fill “j .with Water, or the Air compressed into half the sit"Space, its Spring will be in this Cafe equal to twi c ®the Pressure of the Atmosphere ; and therefore wh e)1the Stop-Cock at p is turned, the Air within pressingon the subjacent Water with twice the Force it meetswith from the external Air in the Pipe ef, will caul®the W ater to spout out of the Engine to the Height o*32 or 33 Feet, if the Friction is not too great.

3. That it must spout to that Height is evident froJp .hence, that only one half the Force of the internal A 1 ®is spent in overcoming the Resistance of the extet'na] Air ; and this being destroy’d, the remaining Hdof the Force will be exerted in projecting the Watt*'?which now must be considered as spouting in Vacuo (th®Resistance of the external Air being taken away). B 11

in Vacuo Water will rife to the Height of 32 or 3 ^Feet (as will be strewn hereafter) by the Pressure of th®common Air ; therefore since the remaining half For® 6of the internal Air is equal to the Pressure of the cosstmon Air, it must cause the Spout to rife to the Heighof 32 or 33 Feet; and because the Water keeps ent e siing the Vessel as fast as it spouts out, it keeps the A lsunder the fame Degree of Compression, which thessj tfore must constantly act with the fame Tenor on "VWater, and produce a continual Stream to the la lTlHeight.

4 . When the Air-Vessel is j full of Water, the Sp a sij ;which the Air takes up is x Part, whence its Spring .be 3 times as great as that of the common Air, th e f e _

th®

fore it will now project the Water with twiceForce of the Atmosphere, and therefore to the HdZ") >of 64 or 66 Feet. Whfen the Air-Vessel is 3 full °‘ i- .Wat® r > s

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