The force of the water in these penstocks is terrific. Tests of a four-inch jet from one of them have been made. A rifle-bullet glances off as from chilled steel; a jet from it, no bigger than a penholder, will drill a hole in sheet steel in a few moments. At the reservoir on the summit a fly-line may be played in the water—at the foot of the penstock no mortal could thrust a bayonet one inch into it.
A United States trooper once essayed, on a wager, to cut a two-inch jet with his sword; a shattered weapon and a broken wrist resulted.
In the harnessing and curbing of these mountain streams the utmost engineering skill and ingenuity has been called into play. Often the power-house has to be situated miles back in such inaccessible wilds that the greatest difficulty has been encountered in carrying machinery and supplies to the spot. At one point in the Sierras men and material were transported across two yawning chasms by means of wire cables, under which ran a freight-carrier.
The Feather River in California makes a big horseshoe bend twenty-five miles above Oroville, coming within three miles of itself again. An enormous mountain intervenes, but the engineers tunneled that and diverted the water into that tunnel. In the lower end of that black, rushing, underground torrent are placed the great turbines and generators.
The most striking instance of the results of securing a big headway for a small stream is shown in San Juan County, Colorado. The Animus River in its course between Silverton and Durango, a distance of twenty miles, has a gradual fall of about fifteen hundred feet. Although called a river, it is but a mountain stream, tumbling over little falls and through rock-strewn gullies, at no point showing more power than would be sufficient to drive a very small grist-mill. But the genius of science has so cunningly diverted it and concentrated its energy as to develop at last 40,000 horse-power.
A dam was built a few miles below Silverton, and the water turned into a flume which is only six by eight feet in size. It will be seen that it must be a very small stream whose waters can be run through such a restricted channel. Across fearful cañons and around great mountains, through tunnels and cuttings that flume carries the water for sixteen miles to the edge of a great cliff near Durango. The cliff is over one thousand feet high, and the pipe runs over the edge and makes a perpendicular drop into the power-house below.
From the four-foot steel pipe, nozzles five-eighths of an inch in diameter conduct the water into the turbines, whirling them at a speed of four thousand revolutions per minute. The speed of the jets of water shooting from those nozzles is 25,000 feet, or over four miles per minute.
Note how the wizards of industry further concentrate and control the giant they have evoked. That forty-thousand horse-power making that mighty plunge over the cliff is met by magical machines and switched into a wire but little larger than a lead-pencil. Forty feet of that unyielding steel flume which held the power is a load for a freight car; forty feet of the wire which carries the power is but a small load for a six-year-old boy.
At one moment the power is in that roaring, headlong, terrific plunge—the next, it is miles away, invisible, noiseless, and mysterious, illuminating great arc-lamps, running heavy cars, and—to come from great to small—whirling dainty fans or cooking an egg.
There are other marvelous power-plants situated on rivers where, although the force is far less than that of the mountain torrents, the volume of water is far greater. Idaho shows the most remarkable of the developments of such water-power, and the astounding ingenuity and determination of the genii are shown as much as in the mountains. The Bear River, which runs through Idaho and Utah, carries a very large flow at an exceedingly rapid rate—for a river. At one point in Idaho no less than six great power-houses have been installed on that river, producing a total of nearly 200,000 horse-power. In order to secure good headway, and the force which this gives, two enormous pipe-lines have been built to take the water from upper reaches of the river, and, while holding that pipe almost to a level, run it across country to a lower reach, where a power-house is built, thus increasing the headway from nothing to two or three hundred feet.