Page:Popular Science Monthly Volume 45.djvu/629

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fact that they are as diverse as the manufacture of "mechanical" wood pulp and the smelting of aluminum.

There are already at the falls a few establishments using power developed by turbines, and which have been quietly at work for years. There is a canal known as the Hydraulic Canal on the American side, skirting the city of Niagara Falls, and terminating on the cliffs, half a mile below the cataract. There are a number of mills here which, for the most part, however, utilize only a fraction of the total fall available, probably for the reason that when they were built there were not in existence the high-grade water wheels suitable for great head that are on the market to-day.

People in general have the idea that the Niagara water power is inexhaustible, and so it probably is, so far as human requirements go. There are, however, some tolerably close data on which to figure the total horse power. The Lake Survey Board and Mr. R. C. Reid, examining the matter independently, have come to a very fair agreement in their conclusions on this point. From their figures it would appear that the average flow is about 270,000 cubic feet per second, and this is almost exactly the same as the almost unthinkable quantity of 1,000,000,000 pounds per minute. A horse power of work is the equivalent of 33,000 foot pounds per minute, and as the weight above mentioned falls 161 feet, the horse power of the total is expressed as follows: close on five million.

Owing to the lack in full efficiency of even the best commercial turbine wheels, we may take the limit of power that could be developed as about 4,000,000 horse power.

The average power is not departed from to any great extent at different sea,sons, as is the case with other water powers, because the spring thaws and summer droughts affect hardly at all the level of Lake Erie, from which the falls get their supply.

The system of Great Lakes above Ontario would require a year in order to have their level reduced by three feet and a half by even the enormous drain of a thousand million pounds of water per minute above referred to, supposing the system to be entirely cut off from its normal supply. A paper by Mr. R. C. Reid before the Royal Scottish Society of Arts in March, 1885, gives the foiling data: Total water-shed area down to Niagara, 290,000 square miles; total lake surface, 92,000 square miles; average rainfall in the lake district, thirty-six inches—and that we may assume twenty inches annually of evaporation and absorption, leaving sixteen inches over the whole area finding its way to the lakes. From the lake surface proper, there occurs evaporation to the extent of twenty-four inches per annum. Further, in reference to the enormous storage capacity of the system, he shows