to the fly-wheel shaft, on which is the pinion driving the spur-wheel attached to the pitman of the pump-bob.  Hoisting is done by two wheels placed side by side on the same shaft, the buckets and nozzle of each wheel being placed in opposite directions.  Both wheels are 8 feet in diameter, with 15/16-inch nozzles, and make at full speed about 225 turns a minute.  Reversing the movement of the shaft is done by shutting off water from one wheel, and turning water on the other wheel; the two water-gates for these nozzles are quickly opened or closed by hydrostatic pressure, afforded from the water main.  In addition to the usual brakes on the winding-reels, a brake is placed on the wheel-shaft, so that it can be stopped in a very short period of time.

The shock to the pipe by the almost instantaneous cutting off the water at these hoisting-wheels (nearly one cubic foot per second) has not apparently had any injurious, effect.  To lessen this shock, a compensating balance was designed, but which is not now in use.  A wheel, of small diameter, is used for the smithy, etc., running at a very high velocity.  The wheel driving the stamp-mill is 6 feet in diameter, makes 300 revolutions a minute, and is supplied through a 1-3/16 inch nozzle.  The head of water at this point is a few feet greater than at the other wheels.  Power is transmitted from the hoisting and mill-wheel shafts by two and four ropes, the same as with the pumping rig.  The amount of work done, or of water used, has not been carefully determined; judging from the indicator cards taken from the old steam-engines, the managers of the Idaho believe that an efficiency of fully 80 per cent. of the theoretic power of the water is obtained on the main driving-shafts of the machinery.  The substitution of water for steam-power has resulted in a large saving of expense.  Although the hills near by are covered with fine forests, thus making wood cheap, and although a round price is charged for water by the company furnishing it, the cost of the water is considerably less than that of the wood formerly used as fuel.  The cost of attendance is altogether in favor of the water-wheels, which hardly require any attention.  The cost of the change from steam to water-power was $46,496.32.

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TEXAS CREEK PIPE AND AQUEDUCT.

A description of this work will be of interest in showing the general practice followed in California for carrying water across deep mountain gorges.  In order to augment its water supply, the North Bloomfield Gravel Mining Company desired to conduct water from a stream known as Texas Creek, in Nevada County, California, across the Big Canon branch of the South Yuba River into the main Bloomfield flume or aqueduct, which was located on the side of Big Canon Creek, at a vertical elevation of 620 feet above the bed of the latter stream.  The quantity of water to be carried was