RECENT WONDERS OF ELECTRICITY. 793 



trie light ; though the electric light does, as I have said, generate 

 heat to produce its effulgence. Many people talk of the electric light 

 as being " cold " and cheerless. The light produced by the arc-lamp 

 does look cold and cheerless ; but the soft, delicious, incandescent 

 lamp before you has just as soothing an effect upon the eye as the 

 prettiest lamps or the pleasantest candle ; and it has certainly re- 

 moved all the objections tbat were previously raised to the electric 

 light for internal illuminating purposes. 



The next and last branch of my subject is the transmission of mo- 

 tive-power to a distance. I have shown you how currents of electric- 

 ity are produced ; also how they do work ; how they produce electro- 

 magnetism ; how they generate heat ; how they produce light ; and 

 now I want to show you that the whole thing is reversible. If, by the 

 exertion of mechanical power, currents of electricity can be produced, 

 those very same currents of electricity can in their turn produce me- 

 chanical power. If, instead of receiving currents of electricity from 

 the dynamo-machine on the Thames embankment, we transmitted cur- 

 rents of electricity to it, we should cause it to rotate, but in the reverse 

 direction. I have here a small machine for the purpose of illustrating 

 this to you ; it is the invention of Mr. Griscom, who has supplied it to 

 a large extent in America for turning sewing-machines. The wires 

 from the hand dynamo-machine are now attached to the Griscom 

 motor, and, when currents of electricity are generated by turning the 

 handle of the dynamo, they are conveyed to the motor, and cause it to 

 revolve with the high rapidity you see. It is surprising that such a 

 tremendous momentum should be produced by so small a strength of 

 electric current. The wires connecting the two machines in this in- 

 stance are short, but the effect would have been practically the same 

 had the machines been miles apart. By changing the wires, the direc- 

 tion in which the motor rotates is reversed, so that I not only get 

 power transmitted, but can reverse its direction. In this case, as the 

 electricity is generated by hand, its power is small ; and, therefore, 

 with my strength (which is only about one twelfth of a horse-power), 

 I can stop the rotation of the motor ; but, if steam-power were em- 

 ployed to generate the electricity, the power transmitted would be be- 

 yond my control in that sense. This motive-power was illustrated, in 

 many different forms, at the Paris Exhibition ; for instance, from the 

 commencement of the Champs-Elysees to the exhibition building, a 

 tram-car was propelled (sometimes at the rate of twenty-five miles an 

 hour) upon rails laid down for the purpose, and, during the time that 

 the exhibition was open, that car carried seventy-five to eighty thou- 

 sand people, who were conveyed to or from the building by motive- 

 power generated by steam in the exhibition and conveyed by wires 

 to the farther extremity of the track. An electric railway will form 

 part of the Electric Exhibition at the Crystal Palace, and among the 

 proposals to be laid before Parliament next session is a project for 



