Page:Philosophical Transactions - Volume 037.djvu/14

 One Revolution of a Wheel makes in every Forcer 2⅓ Strokes

So that one Turn of the 4 Wheels makes 114 Strokes.

When the River is at best, the Wheels go six times round in a Minute, and but 4½ at middle Water 6

The Number of Strokes in a Minute 684.

The Stroke is 2½ Feet, in a 7 Inch Bore, raises 3

Ale Gall.

They raise per Minute 2052

That is, 123120 Gallons = 1954 Hogseads per Hour, and at the Rate of 46896 Hogsheads in a Day, to the Height of 120 Feet.

This is the utmost Quantity they can raise, supposing there were no imperfections or Loss at all.

But it is certain from the Considerations following, that no Engine can raise so munch as will answer the Quantity of Water the Cylinder contains in the Length of the Forcer, or Piston's Motion: For,

First, The opening and shutting of the Valves lose nearly so much of that Column, as the Height they rise and fall.

Secondly, No Leather is strong enough for the Piston, but there must continually slip or squeeze by some Water, when it is raised to a great Height; and when the Column is short, it will not press the Leather enough to the Cylinder, or Barrel; But especially at the Beginning, or first moving of the Piston, there is so little Weight on it, that before the Leather can expand, there is some Loss.

Thirdly, And this Loss is more or less, as the Pistons are looser or straighter leathered.

Fourthly, When the Leathers grow too soft, they are not capable of sustaining the Pillar to be raised.