, the required supply is about 8
cubic feet a second; this draught reduces the effective head to say 523
feet.
The work done consists in driving the following described machinery:
A large air-compressor--2 cylinders, double acting, air compressed to 75
pounds--requiring about 140 horse-power.
A line of Cornish pumps, forcing the water from a depth of 1,450 feet
vertical; 12-inch plungers for upper 800 feet, 6-inch plungers for lower
650 feet, with 6-foot stroke, requiring from 55 to 70 horse-power.
Hoisting from a double-compartment shaft--two connected winding reels,
moving separate cages--requiring 35 horse-power, or more.
A few small machine-tools and smithy forges, requiring 3 or 4 horse-power.
A 35-stamp mill, with concentrating apparatus, etc., requiring about 70
horse-power.
The total amount of power required being say 320 horse-power, for which
seven Pelton hurdy-gurdy wheels are employed.
The power in all cases is transmitted by systems of Manila rope belting;
the rope is 2 inches in diameter; the grooves in the sheaves or pulleys
are slightly oval, so that the rope does not go quite to the bottom; the
ropes are horizontal, and run very slack (no tighteners), with no
appreciable slip; the splices are made very long, to obtain uniformity in
diameter.
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