1899.] SELLEES — TBANSMISSION OF ENERGY BY ELECTRICITY. 57 



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 regu- 

 lation 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 com- 

 panies, and threatened for a while even to destroy the value of the 

 capital invested in this great branch of industry, namely, illumina- 

 tion 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 direct- 

 current 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 exten- 

 sive 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 horsepower; 

 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 utili- 

 zation of power of Niagara Falls, on land above the head of the 



