THE ELECTRIC LIGHT. 567 



will at no distant day triumph over gas. I am not so sure that it will 

 do so in our j^rivate houses. As, however, I am anxious to avoid drop- 

 ping a word here that could influence the share market in the slightest 

 degree, I limit myself to this general statement of opinion. 



To one inventor in particular belongs the honor of the idea, and the 

 realization of the idea, of causing the carbon rods to burn away like a 

 candle. It is needless for me to say that I here refer to the young 

 Russian officer, M. Jablochkoff. He sets two carbon rods upright at a 

 small distance apart, and fills the space between them with an insulat- 

 ing substance like plaster of Paris. The carbon rods are fixed in metal- 

 lic holders. A momentary contact is established between the two car- 

 bons by a little cross-piece of the same substance placed horizontally 

 from top to top. This cross-piece is immediately dissipated or removed 

 by the current, the passage of which once established is afterward 

 maintained. The carbons gradually waste, while the substance between 

 them melts like the wax of a candle. The comparison, however, only 

 holds good for the act of melting ; for, as regards the current, the in- 

 sulating plaster is practically inert. Indeed, as proved by M. Rapieff 

 and Mr. Wilde, the plaster may be dispensed with altogether, the cur- 

 rent passing from point to point between the naked carbons. M. de 

 Meritens has recently brought out a new candle, in which the plaster is 

 abandoned, while between the two principal carbons is placed a third 

 insulated rod of the same material. With the small De Meritens ma- 

 chine two of these candles can be lighted before you ; they produce a 

 very brilliant light.' In the Jablochkoff candle it is necessary that the 

 carbons should be consumed at the same rate. Hence the necessity for 

 alternating currents by which this equal consumption is secured. It 

 will be seen that M. Jablochkoff has abolished reo-ulators altosfether, 

 introducing the candle principle in their stead. In my judgment, the 

 performance of the Jablochkoff candle on the Thames Embankment and 

 the Holborn Viaduct is highly creditable, notwithstanding a consider- 

 able waste of light toward the sky. The Jablochkoff lamps, it may be 

 added, would be more effective in a street, where their light would be 

 scattered abroad by the adjacent houses, than in the positions which 

 they now occupy in London. 



It was my custom some years ago, whenever I needed a new and 

 complicated instrument, to sit down beside its proposed constructor, 

 and to talk the matter over with him. The study of the inventor's 

 mind which this habit opened out was always of the highest interest to 

 me. I particularly well remember the impression made upon me on 

 such occasions by the late Mr. Darker, a philosophical instrument maker 

 in Lambeth. This man's life was a struggle, and the reason of it was 



' Both the machines of M. de Meritens and the Farmer-Wallace machine were worked 

 by an excellent gas-engine, lent for the occasion by the Messrs. Crossley, of Manchester. 

 The Siemens machine was worked by steam. 



