res, as it is difficult to avoid
ruptures with cast and wrought-iron combined, owing to the great
difference in the elasticity of the two metals. The long seams of this
pipe are double-riveted, and the round seams single riveted; at the lower
end, iron of No. 6 gauge is used. From the end of the main, the water is
led to the several wheels by branches of smaller diameter.

[Footnote 4: With buried wrought-iron pipe this precaution is unnecessary,
as the elasticity of the iron will admit of the movement due to changes of
temperature, without injury to the rivets.]

The water is delivered at the hoisting-wheel with a total head of 542.6
feet. For power and for mill uses, etc., 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.

[Illustration: FIG. 15.]

This method of transmitting power appears to work most perfectly and has
given excellent satisfaction. It is thought, at the Idaho, to be greatly
preferable to the gearing formerly in use when the works were driven by
steam (for such work as pumping or hoisting, leather or rubber belting is
never used), besides being much cheaper in first cost.

The wheel driving the air-compressor is 6 feet in diameter, running 300
turns[5] per minute, with 1-15/1