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in support, claim the discovery of some new and heretofore unrecognized power that is to supersede all known forms of energy utilized in the modern means for actuating machinery.

With the first conception of the electric telegraph electricity generated by galvanic batteries was used. The energy of the galvanic battery was transmitted to instruments which produced motion and thus made visible impression upon paper, or later by sound, to convey intelligence through the equivalent of dots and dashes, or by sight noting the vibration of a needle, all of which motions involved the transmission of power, no matter how little might be required for the purpose.

When electricity came to be transmitted for lighting purposes it was not in the form of what was generally accepted as the term power, but it was the transmission of a different form of energy, one only of the many forms that are co-related one to the other. It is in the very last decade of this century that the transmission of power has come to have a meaning of greater importance than was ever dreamed of in Franklin's day, or even when Michael Faraday and others laid the foundation of the mass of valuable knowledge that was ready to be used to advantage when the needs of man called for its practical application.

It is interesting to note that although the actual transmission of power in large amounts by electricity has been carried out chiefly in the last few years, yet what is now being accomplished is the result of knowledge that was obtained quite early in the present century. Faraday's great discoveries began in 1830, and these, with what had been contributed by a host of workers before him, bore fruit before the end of the first half of the nineteenth century.

I will not take up your time with recounting the steps that led up to what forms the substance of our scientific knowledge of electricity, nor to even mention the names of the great men who have contributed to our store of information. With electricity it is very much as in the case of the locomotive, that became an established fact and an important factor in our civilization in 1827, but was anticipated and predicted by those who in a crude way operated steam carriages on common roads before that date; and long before a fairly perfect locomotive was placed upon iron rails the railroad had been demonstrated to be of advantage even with animal traction in mining operations. The iron railroad and the

steam engine on wheels had to be brought together to make a perfect whole.

The beginning of this century saw in our country and by our own people the first great steps taken to make our railroad system of transportation possible through the demonstration of the advantage of using high-pressure steam. This knowledge was necessary even to make the steamboat a commercial success on the inland waters of the United States. On March 2, 1825, at the end of the first quarter of this century, refrigeration by rarefaction of air was being discussed.' This fact will be worth remembering when I come to speak briefly of the recent transmissions of energy by other means than electricity. Prof. S. F. B. Morse, as early as 1832, had formed an idea of his electro-magnetic system of electric telegraphing, and in 1835 he constructed his first recording telegraph instrument and used it on short distances, but it was not until 1843 that Congress, after great opposition, voted the sum of $43,000 to construct the line of communication between Washington and Baltimore, which was put in successful operation by 1844, thus giving an illustration of long-distance transmission of power to energize the magnets that gave motion to the instruments required in telegraphy. On December 16, 1848, Prof. Henry, in his second annual report to the Board of Regents of the Smithsonian Institution, proposed that so far as the funds of the Institution would permit, the magnetic telegraph be used in the investigation of atmospheric phenomena, in order that notice of the approach of storms might be given to distant observers. This was just four years after the electric telegraph had been installed.

On March 19, 1853, forty-six years ago, Prof. Henry, in an address at the close of the exhibition of the Metropolitan Mechanics' Institute at Washington, explained the true relation between power and the means at command for transmitting and utilizing power. He pointed out an error in text-books even of that late day, when elementary machines-namely, the lever, the wheel, the axle, the inclined plane, the pulley and the screw, employed separately as instruments for the application of power, or in combination as parts of complex machines-were classed as "mechanical powers," "when every tyro in science," he says, "knows they have no power in themselves; yet, through a wrong name and

1 See Prof. Jos. Henry's paper on this subject, read before the Albany Institute on the date above mentioned.

a misapplication of the word power, a pernicious error is perpetuated long after the fallacy is understood." He gave a list of what could be classed as the primary powers as used by man. "First, water power; second, wind power; third, tide power; fourth, the power of combustion; fifth, the power of vital action," remarking that "the power of volcanoes and the internal heat of the earth were as yet unused powers." Beyond these few, he says, "science gives no indication of any other." He did not mention the direct heat of the sun as a source of power. He, however, remarked that "Gravitation, electricity, galvanism, magnetism and chemical affinity can never be employed as original sources of power; they are at the surface of the earth forces of equilibrium, the normal condition of which must be disturbed before they can manifest power, and then the work they can do is only (approximately) equal to the power which was communicated to them in disturbing their state of rest."

Electricity is not, he said, in itself a source of power, yet, what is very important from his point of view, "electricity, from its extreme mobility and high elasticity, affords the means of transmitting power with scarcely any loss and almost inconceivable velocity to the greatest distance; a wave of disturbance starting from the impulse given at the battery will traverse the circumference of the earth in less time than I have been occupying in stating the fact." This is interesting, but we are yet far from realizing the consummation of this idea. When Prof. Henry uttered these words the electric telegraph had become a public necessity, energy had been transmitted over great distances and people had ceased to wonder.

"The telegraph," he said, "could not possibly have been invented, the most ingenious synthetical mind could not have contrived the electro-magnetic telegraph, until Galvani and Oersted had made their discoveries." The transmission of power by electricity, however, has been possible, in varying degrees of efficiency, almost since 1832, and yet two years ago, as I said before, I felt that in its highest degree of efficiency I had not the right to say it could be presented, in a satisfactory way, to the American Philosophical Society in a manner worthy of its founder, who of all men of his day thought chiefly of the practical side of such a subject.

When Prof. Joseph Henry spoke of the possibility of transmitting

an electric impulse around the globe, it was the impulse from a gal vanic battery. No dynamo had been used in place of a battery, although instruments had been constructed to demonstrate the fact that the dynamo could be used. The electro-magnet was well understood, the electric impulse had been made to give motion to machines from electro-magnets and from permanent magnets, and the relation of the various forms of energy, represented by light, heat, magnetism, etc., were each and all known to be what has since been termed "modes of motion."

In the year 1876, marking a century in the age of our Republic, there was given to the world, through the grand Centennial Exhibition in Philadelphia, an object-lesson in the state of the arts and the advance of knowledge. The buildings in Fairmount Park, however, were not lighted by electricity, although the arc light, with clockwork to keep the carbons in proper relation to each other, was used for experimental purposes long before. As to the use of the arc light, on the 8th of December, 1858, the high light at South Foreland was illuminated by an electric current generated by one of Holmes' magneto-electric machines. In 1863 the electric light was applied to the lighthouse at La Hève, France. The chemical action of electricity was known when Carlyle and Nicholson discovered in the year 1800 that water could, by means of electricity, be resolved into its two component gases, oxygen and hydrogen, by means of the voltaic pile. Sir Humphrey Davy by the same means, seven years later, proved true Lavoissier's suspicion that the alkalies potash and sodium were not simple bodies, but compound, by the discovery of five new metals by electrolysis, viz., potassium, sodium, barium, strontian and calcium. I shall refer to one of these metals when I come to speak of the transmission of energy from one common source of power in a condition ready for use, either for turning the wheels of factories, for heating, lighting or repeating Sir Humphrey Davy's process in the production of sodium from an alkali, not as a laboratory experiment, but on a commercial scale at the rate of many tons per day.

In tracing the progress of knowledge bearing upon the transmission of energy by electricity, the United States Patent Office records furnish much information of a historical character useful for determining the chronological sequence of invention, and no more interesting chapter in the history could be obtained than that on the application of the modern dynamo by telegraph companies to

supersede the galvanic batteries that for so many years supplied the electricity needed for their purpose.

There are to be found a number of patents relating to the regulation of the electro-motive force from the dynamo to equalize the pressure on lines of different lengths and different resistances. It was not, however, until lighting by electricity became a necessity in the most recent times that the great demand for electric machinery for lighting purposes, which so alarmed the gas companies, and threatened for a while even to destroy the value of the capital invested in this great branch of industry, namely, illumination by gas, became a commercial necessity. It was then that mechanical engineering talent of a high order was added to the electrical knowledge of the time to increase the efficiency of directcurrent dynamos for lighting and for furnishing power in small amounts. Large establishments sprang up in Europe and in America for the manufacture of electrical machinery on an extensive scale, finally leading to the foundation of the present great corporations, whose stock is quoted among the "Industrials" listed on the Stock Exchanges of the country. Ten years ago, in 1889, these companies were doing a thriving business; yet at that time there had been little accomplished in the direction of the actual transmission of power by electricity, in contradistinction to the transmission of energy for lighting purposes.

I have preferred to entitle my discourse "The Transmission of Energy" rather than of "power," because the latter term serves rather to suggest kinetic energy, or the energy of matter in motion, while electricity permits the transmission of many sorts of energy. The turbine wheels at Niagara, nominally of 5000 horse power, generate kinetic energy from the water put in motion by gravity. The dynamo driven by the turbine delivers 5000 electric horse power; so efficiently is the change from kinetic to electric energy effected in this case by the dynamo that all the electric and magnetic losses in that part of the machinery amount to less than two and one-half per cent., apart from the losses due mechanical friction and windage, which are light as compared to what has been done by smaller units of power.

In the autumn of 1889 I was asked to submit a report on the transmission of power by electricity by gentlemen who had become interested in what was then known as the Evershed scheme of utilization of power of Niagara Falls, on land above the head of the

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