4 ELECTRIC LIGHTING. 



it over several places, the superintendence which it was ne- 

 cessary to bestow on the working of the electric lamps, and 

 the irregularity of their action, discouraged even the most 

 sanguine. It is only in quite recent times after fresh im- 

 provements in the electric machines, in the carbons of the 

 lamps, in the lamps themselves, and particularly after the 

 interesting experiments made by the Jablochkoff Company 

 i-n lighting streets and private establishments that the ques- 

 tion has again come to the front, but this time under infinitely 

 more favourable conditions, which promise its speedy solu- 

 tion. To judge by the flutter in gas companies' stock in 

 England, as well as in France and America, we may conclude 

 that the matter has become serious, and that we shall pro- 

 bably in a few years hence witness the at least partial 

 transformation of public illumination. 



IMPORTANT DEFINITIONS, 



Before entering into any detail on matters relating to the 

 electric light, it appears to me indispensable to clearly lay 

 down the meaning that must be attached to certain words 

 which we shall often have occasion to use, and which, though 

 perfectly precise and definite in their signification, are not 

 always rightly understood, and hence much deplorable con- 

 fusion often arises. 



In the first place an electric current is, in fact, nothing in 

 itself 'but a dynamical action or motion resulting from the 

 destruction of electrical equilibrium in a conducting system, 

 its effect being a tendency to the re-establishment of the dis- 

 turbed equilibrium through the medium of another conductor. 

 Consequently, if the cause which has produced this destruc 



