T By Elihu Thomson. RUE science, bound by no fetters, its theories tenable only so long as they are useful in connecting facts, its progress limited only by the life of the race on the earth, and its field unbounded, - is not only vastly enlarging the mental horizon, but is, at the same time, conferring incalculable practical benefits. Did this statement need emphasis, it is found in the growth of no particular branch of science more than in electricity. While in the near past the extension of its industrial applications has been phenomenal, we must not forget that during the same period its theories have become equally expanded and shorn of crudity. nearly two hundred thousand miles per second. So are also other electrical actions. With the vast accumulation of new facts, electricity has come to be understood as intimately related in its nature and actions to that necessary something which has been called the universal ether, filling all space and permeating the most solid objects. By the electrical vibrations of this medium, the stars not only declare their very presence, but transmit to us indications of their directions and rates of motion, their temperatures, and even the kind of matter which composes them. The beam of light is an electrical phenomenon, it is an electrical oscillation or vibration of such extraordinary rapidity, hundreds of trillions per second, as to become unrealizable in thought. It is conveyed in the ether at the rate of It would be outside the scope of an article like the present to dwell upon the possible directions of development of electrical theories in so far as they may include other phenomena than light, so recently demonstrated to be electrical in its nature. The fact that electrical action is so intimately related to the phenomena of heat, chemical energy, and crystallization leads us to think that future discoveries can but tend towards further harmonies of these great forces. Electrical attraction and repulsion, magnetism, light, and radiant heat are now known to be dependent in some way on the properties of the ether of space. Gravitational force must be similarly dependent. Cohesion and chemical affinity are, without doubt, manifestations depending on the same medium. The future scientific investigator will find his field of work gradually expanding. The growth of electricity as a branch of science must be at least commensurate with that of the broader science of physics. But let us turn to a brief consideration of the possible advances in the practical applications of electric energy in the arts and industries. Let us examine the subject from the standpoint of effect on our methods of work and conditions of life. There is required no special scientific taste or training to enable people to appreciate immediately practical aspects. As a swift messenger, as a conveyer of intelligence, electricity has in the telegraph been familiarly known for about half a century. So far as appears from the present outlook, future telegraphic progress promises no great revolutions. Methods and means will, no doubt, become more and more refined, and greater speeds be attained. The more general introduction of multiplex systems will increase the capacity of the lines and decrease the costs. More attention will be given to permanence of lines and to securing immunity from extended interruptions due to storms. It may be remarked here, however, that electricians are not without some hope that signalling or telegraphing for moderate distances without wires, and even through dense fog may be an accomplished fact soon. Had we the means of obtaining electric oscillations of several millions per second, or waves similar to light waves, but of vastly lower rate of vibration, it might be possible by suitable reflectors to cause them to be carried a mile or so through a fog, and to recognize their presence by instruments constructed for the purpose. Many of the difficulties and dangers which now beset the navigator would, at least, be lessened, if not removed. Signalling or telegraphing without wires is no new proposal, and there have been many such proposals which are extravagant and impracticable. The fact is, however, the essential means are not yet forthcoming. In telephonic transmission the past few years have permitted us to witness extensions from communication over restricted areas and moderate distances to hundreds of miles between cities, an achievement which must count as one of the wonders of the century. The telephone itself, even when first brought out, was a marvel of simplicity and effectiveness. When we consider that by its means we may converse with and even recognize the voice of a person distant from us a considerable fraction of the earth's circumference, we cannot fail to be impressed with the wonder of it. Can we, however, anticipate such an extension of the power of the telephone, that we may at some time use an ocean cable as the line over which speech is to be conveyed? To answer this question in the negative would be to set a limit to the capacity of the human intellect to make future advances; nevertheless, there are reasons which are cogent enough tending to point to the impracticability of telephonic transmission through cables of great length. In such cases a retardation and an obliteration of the delicate pulses of current which characterize electrical speech serve to prevent the reception of speech at the far end of the line. By enormously increasing the power of the waves or impulses, the difficulty would be, in a measure, overcome, but to do this introduces other grave difficulties, the solution of which is not easy to foresee. The idea of lighting by wire or carrying electric current from its source to lamps in which the electric energy is transformed into light, long preceded the invention of the telephone, and many notable efforts were long ago made in the field of electric lighting. But to be able to speak over miles of wire was a feat well calculated to impress upon the public the possibility that so wonderful an agent as electricity might possess other capabilities perhaps only suspected by some of the more sanguine inventors and scientific students. We need not wonder that electric lighting as an industry sprang into existence quickly and gained public favor soon after the birth of the telephone. Much of the preliminary work. had been done long before. It only needed inventive genius to adapt to the present needs the information which had been accumulated. It is not to be denied that many difficult problems had to be worked out, but it is an actual fact that the groundwork for the development of the art of lighting by the electric arc and by incandescence had been laid many years before these became a part of the industries. What shall we say of the future of an art which in the past ten years has so firmly rooted itself as a factor in our civilization? it a proportionate Can we predict for expansion in the 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. But 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 thousand lamps of ordinary power, but to-day machines of five thousand to ten thousand lamps capacity are constructed, the larger sizes requiring about a thousand horse-power to drive them. SHIP Office WAVE Signal improvements and refinements, in response to the needs of the electrical engineer, and has to-day reached a fairly perfect state. Its most economical type for large powers is called "compound condensing," in which the steam at high Electricity for lighting is now almost pressure undergoes successive expansions 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. |