altogether produced by the expenditure of steam-power or water-power. Its cost, therefore, outside of the interest, wear, and tear, and running expense, is largely dependent on the cost of power. The steam-engine itself has undergone many

future? Will electric light replace gas and kerosene oil lighting? These are questions which naturally suggest themselves and which can be answered only in a general way, because the advent of some new discovery, perhaps unanticipated, or perhaps among those things for which we are looking may change the whole face of matters.

That electric lighting will grow at an increased and increasing pace cannot be doubted. There were many in the early days of lighting by the arc who were ready to pronounce the field of its application very limited, and some there were, even among electricians, who were credited with the prediction that arc lighting would be superseded in a few years.

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the enormous number of arc lights now in use and the constant rapid extension are but indications of a future of not less importance than the past. So also in the field of lighting by the use of incandescent lamps, the growth has in the immediate past been very great. A few years ago machinery for supplying electricity to work the lamps would have been considered as of quite large capacity if able to supply five hundred to one improvements and refinements, in rethousand lamps of ordinary power, but sponse to the needs of the electrical to-day machines of five thousand to ten engineer, and has to-day reached a fairly thousand lamps capacity are constructed, perfect state. Its most economical type the larger sizes requiring about a thou- for large powers is called "compound sand horse-power to drive them. condensing," in which the steam at high Electricity for lighting is now almost pressure undergoes successive expansions

in yielding its power. When the pressure is thus very greatly reduced, the steam is finally condensed, and is thus relieved of the burden, so to speak, of overcoming the pressure of the atmosphere in escaping from the engine. The best type of triple expansion condensing engines will yield power at a consumption of less than two pounds of good fuel per horsepower for an hour, ordinary engines requiring from three to five or more pounds for the same work. It is not to be wondered at, then, that much attention is being drawn to the use of such perfect engines in electric stations. The future will see many of the large stations remodelled to secure the advantages of economy only obtainable with the best type of engines. Cheaper power means cheaper light. Hence, also, much attention has been directed to the use of water-power for driving electric machinery; and it is not unusual now to find the lighting of a town or a city accomplished by the use of water-power, in some cases ten to fifteen miles distant. Our means or methods of distribution and transmission of the electricity will in the future doubtless undergo improvements which will permit the economical use of power at much greater distances than is now attempted. Our great giant power, Niagara, having spent its energies for ages in useless pulverizing of rock masses, will be

Power Station at Niagara

made to exert its strength to turn great dynamos for lighting and power transmission to greater and greater distances. Other great water-powers are gradually being taken up for investigation with the same object in view. The electricity generated in such cases is not, of course, limited to employment for lighting, but, through that almost perfect machine, the electric motor or reversed dynamo, it may be turned back into power with but small loss. Let us inquire what the loss in such cases may be. It varies in accordance with the scale of operations. Dynamos of two or three hundred horse power capacity

Distributing Station, New York City.

obtainable for use represents scarcely more than ten per cent of the real value of the fuel under the very best conditions, the question arises whether there may not be discoverable a plan whereby a much larger percentage of the real value of the fuel may be turned to account as electricity, and through the latter as heat, light, or power. This question has at present no answer. The subject has been alive in the minds of our most able engineers and inventors for years, and some have striven hard to find a solution to the problem. Records of scientific discovery have been earnestly ransacked to find some clue; or, as it were, a guiding post to point the way for the uncertain explorer. It now appears that we may be compelled to await some new discovery, some new adaptation, or some new generalization before the way to the much desired solution may be found. The effect on the general industrial and economic development in electricity which would follow the discovery of some not too complex means for realizing an economy of even 40 or 50 per cent of the energy value of fuel is indeed almost incalculable. Then truly would electricity become the almost universal agent in the production as well as the transmission of power. The steam-engine would go out of use almost entirely. We should burn our coal, not under steam boilers; it would be consumed in electric generators. Our steamships would have their machinery replaced by such