72

!

Hydraulics.

which being set over a Fire, and made tstboil, will fill the upper Part D B E with ?vastly elastic Vapour, the sufficient Strengthwhereof is known by its forcing open ?Valve at e: This heated elastic SteaflVis, by turning a Gock at F, let into theBarrel abed , where by its elastic Force Araises the Piston G, which drives the Ahabove it through a proper Clack at theTop. After this, that the Piston may hf

its

Pump. AMNL is a Collar of Leathers so fixed opthe Top of the Barrel, and adapted to the Rod, that?may move freely in the Leathers, without permitting t? eAir to pass in or out between. The Nozzle or SpoctD has a Stop-Cock 8 to shut off the Water, or let ?pass out as required. Q_ is a Piece screw’d on to dirrect the Stream by a small pliant Leathern Pipe at tb eEnd.

7. Now ’tis plain, when the Piston is raised from tUjBottom of the Pump Barrel, the Water above it W 1 'be forced into the Air Vessel, and there compress thAir (the Stop-Cock being shut); it will also comps° jthe Air on the Top of the Barrel, for the Water W 1not be higher than the Spout D at first, when the StossCock is strut: But afterwards, as the Air is confiu’ 0 .’it will be compress’d at Top, and the Water will r?to I.

8. This compress’d Air, in each Place, will act up 0 ?the Water by its Spring, and, upon turning the St°P^Cock, will force it out in a continual Stream, through 'a Pipe at Q_, and that with a greater or lesser

of Force, as Occasion requires, that being absolute -jn the Power of the Person working the Pump. T? 1 :Invention we owe to the late Sir James Creed.