A short distance farther up the river at the Dufferin Islands is the beginning of the mammoth steel conduits of the Ontario Power Company. These pass about a hundred yards from the shore and conduct the water to the power-house situated in the canyon below the Falls. This contrivance for water transmission consists of three steel pipes, the largest in the world, eighteen feet in diameter, and a little over six thousand feet long. This plant has the advantage of the others in several respects. While it draws its water from farther up the river, it preserves it for a longer time from the recession of the Falls, besides securing to it the greater amount of power per volume by obtaining the additional advantage of the descent of the rapids which amounts to about fifty-five feet. The power plant located as it is in the Gorge discharges its waste waters directly into the lower river without the necessity of an intervening tunnel. Lastly, the plan of applying the power to the turbines is slightly different in this case from the others, being made possible by its different plan. Here the turbines are placed vertical instead of horizontal, and are directly connected with the main generators, which are the only machines located on the floor of the station.
A departure from the ordinary construction of the dynamo is noticed in those for use at Niagara. The ordinary one is built with the field-magnets so placed that the armature revolves between them, the field-magnets being stationary. In these monster dynamos, developing thousands of horse-power, and weighing many tons, the field-magnets revolve around the armature which remains stationary. With such an enormous weight of swiftly revolving parts, it became necessary to lessen the immense centrifugal force tending to tear the machine to pieces. Engineering skill surmounted this problem as it did all others in what might be called this mighty scientific drama, and, by reversing the parts of the dynamo, secured the desired result. The field-magnets, being placed on the outside and being made the revolving part, by their mutual attraction for its armature within their ring are pulled, as it were, toward the centre, thus lessening the great strain produced by the centrifugal force upon the large steel ring upon whose inner circumference they are mounted.