"By engines driven with power supplied by our great oscillator wherever we care to erect it. These engines will work with such incredible force that they will make of the air above them a veritable rope to sustain them at any desired altitude, while they will make of the air in front of them a rope to pull them forward at a high rate of speed." Tesla continues to say that these ships can be made just as large as it is practicable to make their landing stages, or small enough for one or two passengers. In the waterfalls of the United States alone, he pointed out, there are twenty-five hundred million horsepower of electrical energy. Niagara Falls could supply more than one fifth of all the power now used in this country, he says. Moreover, none of the great sites, such as those in the far Northwest, are developed to their highest state, because of the difficulty in transmitting the power over long distances to where it is used. "It must be borne in mind," said Tesla, "that electrical energy obtained by harnessing a waterfall is probably fifty times more effective than fuel energy. Since this is the most perfect way of rendering the sun's energy available the direction of the future material development of man is clearly indicated. He will live on 'white coal.'" "Doctor Tesla, can you tell us, please, just how far you have developed this invention for the wireless transmission of power?" "Well," answered the electrical inventor, "the best way to tell you is to show you what has been done so far." In order to see Tesla's great plant we must follow the scientist and his boy friend out to Bay Shore, L. I., where, overlooking Long Island Sound, we see a great mushroom-shaped steel network tower surmounting a low building--the first of Tesla's many proposed high potential magnifying transmitters. "So far," said Tesla of his power plant where the first attempts at wireless transmission are being made, "only about three million horsepower has been harnessed by my system of alternating current transmission. This is little, but it corresponds nevertheless to adding to the world's population sixty million indefatigable laborers, working virtually without food or pay."