1879.J on tlte Electric Light. 17 



wheel. Again tlio positive carbon wastes more profusely than the 

 negative, and this is alleged to be due to the greater heat of the 

 former. It occurred to Mr. William Siemens to chill the negative 

 artificially, with the view of diminishing or wholly preventing its 

 waste. This he accomplishes by making the negative a hollow cone 

 of copper, and by ingeniously discharging cold water against the 

 interior of the cone. His negative copper is thus caused to remain 

 fixed in space, for it is not dissipated, the positive carbon only needing 

 control. I have seen this lamp in action and can bear witness to its 

 success. 



There is something bewildering in the recent rush of constructive 

 talent into this domain of applied electricity. The question and its 

 prospects are modified from day to day, a steady advance being made 

 towards the improvement both of machines and regulators. With 

 regard to our squares, quays, esj)lanades, public halls, and other 

 similar places, I strongly lean to the opinion that the electric light 

 will finally triumph over gas. I am not so sure that it will do so in 

 our private homes. As, however, I am anxious to avoid dropping 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 honour 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 insulating substance like plaster of Paris. The carbon rods 

 are fixed in metallic holders, by one of which the current arrives, and 

 by the other of which it passes away. A momentary contact is 

 established between the two carbons 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 afterwards 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 insulating plaster is 

 practically inert. Indeed, as proved by M. Rapieff and Mr. Wilde, 

 the plaster may be dispensed with altogether, the current 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 machine two 

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

 brilliant effect.* In the Jablochkoff candle it is necessary that the 

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



* Both the machines of M. de IMeritens 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. 



Vol. IX. (No. 70.) o 



