Meanwhile, it is gratifying to reflect that for the present the Falls retain their pristine beauty, even though part of the water that is their normal due is turned aside and made to do service for man in another way. There is only one reason why the Falls have escaped desecration so long as they have; that reason being the very practical one that until quite recently man has not known how to utilize their powers to advantage. The effort was indeed made, a full generation ago, through the construction of the canal leading from the upper river to the bluffs overlooking the gorge below the cataract. Here a few mill-wheels were set whirling, and a tiny fraction of the potential energy of the water was utilized. There was no mechanical difficulty involved in the utilization of this power. Mill-wheels are a familiar old-time device, and even the turbine wheel is modern only in a relative sense of the word. And it must be understood that the turbine water-wheel utilizes the greatest proportion of the power of falling water of any contrivance as yet known to mechanics. It was possible, then, to utilize the water of Niagara with full effectiveness fifty years ago, so far as the direct action of the water-wheel upon machinery near at hand was concerned. The sole difficulty lay in the fact that only a small amount of machinery can be placed in any one location. The real problem was not how to produce the power, but how to transmit it to a distance.
THE TRANSMISSION OF POWER
For fifty years mechanical engineers have looked enviously upon unshackled Niagara, and have striven to solve the problem of transmitting its power. It were easy enough to harness the great Fall, but futile to do so, so long as the power generated must be used in the immediate vicinity. So, many schemes for transmitting power were tried one after another, and as often laid aside. There was one objection to even the best of them—the cost. At one time it was thought that compressed air might solve the problem. But repeated experiments did not justify the hope. Then it was believed that the storage battery might be made available. The storage battery, it might be explained, does not really store electricity in the sense in which the Leyden jar, for example, stores it. Rather is it to be likened to an ordinary voltaic cell, the chemical ingredients of which have been rendered active by the passage of the electric current. The active ingredients of the storage battery are usually lead compounds, which through action of the electric currents have been decomposed and placed in a state of chemical instability. The dissociated molecule of the lead compound, when permitted to reunite with the atoms with which it was formerly associated, will give up electrical energy.
Such a storage battery might readily be charged with electricity generated at Niagara Falls. It might then be conveyed to any part of the world, and, its poles being connected, the charge of electricity would be made available. Such storage batteries are in common use in connection with electric automobiles, as we have seen. But the great difficulty is that they are enormously heavy in proportion to the amount of electricity that they can generate; therefore, their transportation is difficult and expensive. In practice it is cheaper to produce electricity through the operation of a steam engine in a distant city than to transmit the electricity with the aid of a storage battery from Niagara. So the storage battery served as little as compressed air to solve the engineer's problem.
When the electric dynamo became a commercial success for such purposes as the operation of trolley lines it seemed as if the Niagara problem was on the verge of solution. And so, in point of fact, it really was, though more time was required for it than at first seemed needed. The power generated by the dynamo could, indeed, be transmitted along a wire, but not without great loss. Sir William Siemens, in 1877, had pointed out in connection with this very subject of the wasted power of Niagara, that a thousand horse-power might be transmitted a distance of, say, thirty miles over a copper rod three inches in diameter. But a copper rod three inches in diameter is enormously expensive, and when Siemens further stated that sixty per cent of the power involved would be lost in transmission, it was obvious that the method was far too wasteful to be commercially practicable.
For a time the experimenters with the transmission of electricity along a wire were on the wrong track. They were experimenting with a continuous current which, as we have seen, is produced from an ordinary dynamo with the aid of a commutator. But hosts of experiments finally made it clear that this form of current, no matter how powerful it might be, is unable to traverse considerable distance without great loss, being frittered away in the form of heat.
But the very term "continuous current" implies the existence of a current that is not continuous. In point of fact, we have already seen that a dynamo, if not supplied with a commutator, will produce what is called an alternating current, and such a current has long been known to possess properties peculiar to itself. It is, in effect, an interrupted current, and it is sometimes spoken of as if it really consisted of an alternation of currents which move first in one direction and then in another. Such a conception is not really justifiable. The more plausible explanation is that the alternating current is one in which the electrons are not evenly distributed and move with irregular motion. Perhaps we may think of the individual electrons of such a current as oscillating in their flight, and, as it were, boring their way into the resisting medium. In any event, experience shows that such a current, under proper conditions, may be able to traverse a conducting wire for a long distance with relatively small loss.
It must be understood, however, that the mere fact that a current alternates is not in itself sufficient to make feasible its transmission to a remote distance. To meet all the requirements a current must be of very high voltage. This means, in so far as we can represent the conditions of one form of energy in the terms of another, that it shall be under high pressure. Fortunately a relatively simple apparatus enables the electrician to transform a current from low to high voltage without difficulty. And so at last the problem of transmitting power to a distance of many miles has been solved. Electrical currents representing thousands of horse-power are to-day transmitted from Niagara Falls to the city of Buffalo over ordinary wires, with a loss that is relatively insignificant. A plant is in process of construction that will similarly transmit the power to Toronto; and it is predicted that in the near future the powers of Niagara will be drawn upon by the factories of cities even as far distant as New York and Chicago. Practical difficulties still stand in the way of such very distant transmission, to be sure, but these are matters of detail, and are almost certain to be overcome in the near future.
All this being explained, it will be understood that the sole reason why the new power-houses at Niagara generate electricity is that electricity is the one readily transportable carrier of energy. We have already explained that there is loss of energy when the steam engine operates the dynamo. At Niagara, of course, no steam is involved; it is the energy of falling water that is transformed into the energy of the electrical current. Moreover, the revolving dynamo is attached to the same shaft with the turbine water-wheel, so that there is no loss through the interposition of gearing. Yet even so, the electric current that flows from the dynamo represents somewhat less of energy than the water current that flows into the turbine. This loss, however, is compensated a thousandfold by the fact that the energy of the electric current may now be distributed in obedience to man's will.