THE AGE OF ELECTRICITY. 171 



haud-rail maker, M. Gramme, who was working as a joiner in electric 

 works, made himself acquainted, by uncommon perseverance, with the 

 machines that came under his observation. In 18G9 he devised the ad- 

 mirable contrivance which justly bears the name of gramme ring, and 

 accomplished actual industrial machines. 



The gramme ring is in the nature of an artifice which makes it pos- 

 sible to extract from the inductive alternating effects a manner of 

 rippling stream. Save a few direct applications of the alternating 

 currents, as to light-houses, for instance, this may be said to have been 

 the origin of industrial electricity^ A few years later, 200-horsepower 

 dynamos were built. There was a 2,000-horsepower dynamo on exhi-' 

 bition at Chicago. The power of these machines is boundless. Elec 

 tricity receives the energy of steam engines or waterfalls, transforms 

 it, utilizes it, distributes it, transmits it to long distances, again receives 

 it, and returns it in the most varied forms. 



A new revolution is at hand. By a strange vicissitude of human 

 afltairs we are now retracing our steps. Those alternating currents that 

 seemed so fractious are now tractable. Of easier production, since they 

 require no correcting device, they are transformed by raising their level, 

 so that they may cover long distances at small cost, then by bringing 

 the sluices down for direct api)lication. 



These are strange rivers, witli no tangible flow, whose waters move 

 only by oscillation, whose alternating flow and height of fall may be 

 modified at will, and that are capable of supplying at all times the 

 same amount of effective power, leaving out leakage on the way and 

 invisible friction. 



It was not easy to imagine that a sort of tide, the ebb and flow of 

 which follow each other in less than a twenty-fifth of a second of time 

 could be made available to operate hydraulic wheels and turbines. We 

 now know how to do this. 



If the receiver moves in the same period as the alternating current, 

 the eftects of the impulsion produced by the successive shocks are 

 cumulative; the api^aratus is a synchronous motor. 



If the conductive wires bring several alternating currents, these are 

 regulated so as to operate at stated intervals during a period, in the 

 same manner as the two rods of a locomotive; these are the revolving 

 motors. 



Other contrivances occur to our mind, but to dwell upon them would 

 take up too much time. 



The Niagara Falls will, in the near future, furnish a striking illustra- 

 tion of the application of electricity; 5,000- horsepower turbines, the 

 most powerful ever built, will produce formidable alternating currents 

 which will be easily regulated, transformed, transmitted, and availed of 

 for all purposes. 



At this day electricity transmits instantaneously the human thought 

 through oceans and over continents; it enables us to hear the voice 



