Lord Kelvin, when visiting Niagara Falls, was not moved by that which appeals to the ordinary tourist, the roaring of the cataract, the waters in their mad rush from the Falls to the whirlpool and thence to Lake Ontario, nor the mists rising night and day from the waters churned into foam. For him, Niagara was a monster piece of machinery, accomplishing nothing but the pounding out of its own life on the rocks which formed its bed. In his mind's eye there appeared vast factories, deriving their power from the Falls, furnishing hundreds of men employment and distributing millions of dollars' worth of products to be placed nearer the hands of the poorer classes because of having been created by the cheap power furnished here by nature. Various estimates have been made regarding the volume of water flowing over the Falls; but the calculations by United States engineers extending over a number of years places the amount at about 224,000 gallons a foot per second. These are the figures taken as the basis of many calculations; upon this basis the Falls would furnish 3,800,000 horse-power exclusive of the rapids. If the fall of about fifty feet which is produced by the rapids in their descent from the Dufferin Islands be added to this amount, the sum total of power would be greatly increased. To make some use of this almost inconceivable amount of power which has been wasting itself for ages has been the problem which has caused much investigation and to-day it seems to be nearing a practical solution. Niagara Falls were first used as a source of power in 1725, when a primitive saw-mill was built just opposite Goat Island to saw lumber for the construction of Fort Niagara. For years men have made many attempts to use some of the power to be had here for the taking, and in a very small way have been successful. A number of establishments for several decades have been making use of power developed by the Falls by means of the Hydraulic Canal on the American side. This canal was begun in 1853 and passes through the city of Niagara Falls, terminating on the cliff half a mile below the cataract; here are to be found a number of mills, which however utilise only a small fraction of the fall available, probably because at the time of their construction, the high grade water-wheels of to-day were not in existence. Some of the waste water from the tail races of these mills is now being collected into large iron-tubes and is used again by mills situated at the base of the cliff. [Illustration: Bird's-eye View of the Canadian Rapids and Fall. From a photograph by Notman, Montreal.]