Page:A hundred years hence - the expectations of an optimist (IA hundredyearshenc00russrich).pdf/125

 engines. In a few places (especially in the Niagara valley) waterfall power is used. But whatever the real source of power, electricity is only a means, more or less convenient, of transmitting it. Even electric launches, and slow-going electric broughams driven by accumulators, only represent slightly more subtle examples of the electrical transmission of power. The ultimate source of power is always either a steam-engine or a waterfall. A few lecture-table toys and the like are the only existing examples of machinery in which the actual source of power is electricity. Even here, it may be objected, the actual source of power is not electricity, but chemical action in the battery. But no contrivance of man is an ultimate source of power. Even a steam-engine is only a device for utilising the stored solar energy of coalOf course man can no more create power than he can create matter: the stock of each in the universe is a fixed quantity. All that we are able to do is to harness to our use a part of the cosmic store. When I speak of electricity becoming hereafter a "source" of power, I am merely distinguishing between its use as a means of transmitting force already perceived as force in some other form (as where a dynamo-electric machine receives motion from a steam-engine or waterfall and turns this motion into electricity, which is conveyed by wires or rails to an electric dynamic engine that reconverts