Page:Philosophical Transactions - Volume 037.djvu/15

 Fifthly, If they are leathered very tight, as to lose no Water, then a great Part of the Engine's Force is destroyed by the Friction.

By some Experiments I have accurately made, on Engines whose Parts are large and excellently performed, they will lose and sometimes ¼ of the calculated Quantity.

However, the Perfections or Errors of Engines are to be compared together, by the calculated Quantities or Forces; for as they differ in those, they will proportionably differ in their actual Performances.

The Weight of the Pillar. of Water on a Forcer 7 Inches Diameter, and 120 Foot high.

7 x 7 = 49lb The Pounds Averdupoise in a Yard nearly.

40 Yards high.

1960 lb on one Forcer.

8 Forcers always lifting.

The whole Weight 1568lb = 140Ct. = 7 TunWeight on the Engine at once.

Then the Crank pulls the Libra 3 Feet from the Forcer, and 8,3 Feet from the Center,

7 Tun

× 11.3

8,3)79.1 (9,5 Tun on the Crank. Tun.

Wallower 2,2)9,5(4.3 on Trundle;

The Spur Wheel 4

The Radius of the great Wheel 10) 17,2 1,72 Tun.

20

The Force on the Floats 18 Ct. 40 lb 34,40 Ct.

But to allow for Friction and Velocity, may be reckoned 1 Tun ½.