largest steel conduit in the world, which runs not far from the shore of the river, skirting the other plants, and terminates at the power-house situated in the canyon below the Falls. It is interesting to visit and survey these hydro-electric power-generating stations, to note the different methods for taking the water from the river and for carrying it to the lower river after having passed through turbine wheels. It is well here to take a brief résumé of the main features connected with the obtaining of this water supply and its disposal. The first American company, that of the Niagara Falls Hydraulic Power and Manufacturing Company, takes its water through a canal from the upper river. This canal passes through the centre of the city of Niagara Falls to the cliff just below the first steel cantilever bridge, the power plant and industries making use of its waters are located here at the top of the cliff. The other American company known as the Niagara Falls Power Company takes its water by a short canal, about a mile above the Falls and discharges the dead water through a tunnel that runs under the city of Niagara Falls to a point near the water's edge in the lower river directly below the first steel bridge. The Canadian Niagara Falls Power Company, allied with the American company, takes its water from Queen Victoria Park and discharges it below the Falls through a two thousand foot tunnel. The Toronto and Niagara Power Company, with its power plant built in the bed of the river near Tempest Point takes water through massive stone forebays in the river and sends it to the lower level through a tunnel beneath the river's bed opening directly behind the V in the Horseshoe Falls. The Ontario Power Company takes its water into large steel conduits near Dufferin Islands. These underground pipes conduct the water along the shore of the river to the power house situated on the lower level. The waste water is discharged through draft tubes directly into the river. With this general picture of these great power companies in mind, it is proper to survey some of the more interesting details of construction which may appeal to individual taste and curiosity. Space forbids entering into the minutia either of construction or machinery used. Only the main principles of interest to the general reader can be touched upon.