62

Hydraulics.

there, upon turning the Cock, suffered topass through a Pipe -5, fixed to a Ball an&

Socket)

PI. XX.F‘g- Z,

and 4 to-gether.

yet acting on the very fame Principles as this comply*Pump under Consideration. The Syphon is HGF^N S M, where H GF is the Water Pipe as in the Pump >Z N represents the inner cylindric Tube, and M S th?outer one ; OFZ Q_is the Barrel in which the PistolV X moves (which is a Forcer, or without a Valve)and C R a Conduct-Pipe to carry away the Water forcedthrough the Valve E. In all this it is easy to see th SAnalogy between this Syphon and the mercurial Pump'Its Operation likewise is the same.

50. For let Mercury be poured into the Legs M ^and Z N, it will come to a Level at a, b. Now sup'pose the other Part of the Syphon full of Water, aU®the Piston raised, ’tis plain the Water at H cannot op eItthe Valve I, till a Column of Mercury be raised in theLeg ZN above the Surface of that in the outer L e $M S, sufficient to balance the Weight of the Wa^in the Pipe H F, then will the Pressure of the Air h eequal upon the Water H, and the Mercury in the Le 5MS; and as the Motion of the Piston is continuesthe Water and Mercury will continue to rife with eqU^Momenta, and therefore the Mercury will rife x In ctlfor every 14 Inches nearly, till the Piston stops.

51. When this happens, the Surface of the M es 'cury in the Leg Z N will be at c, and that in theMS at d-, and now, if the Piston be puslied doV|Jagain, it will cause the Water to shut the Valve 1 , ahto act on the Mercury at c, and on the Valve atbut the Presture of the Air at E will not suffer ^Valve to rise till the Pressure there be greater with* 1 )than without, which it cannot be till the Surface °Mercury in the outer Leg MS be higher than that ***the inner one; wherefore, before the Valve E can op efl jthe Mercury in each Leg must come again to the L eVsCa, b ; after which, the Mercury will rise in the ot&fLeg M, so as to be always in Equilibria with the V/ ^ter in the Conduct-Tube RC, and the Part C‘ ,

th 6