226 ELE CTRIC LIGHTING. 



the light ; but it may be feared that some inequalities may 

 in time occur and destroy the uniform diffusion of the light. 

 The expenditure of motive power for 20 Jablochkoff candles 

 worked by a dividing Gramme machine is, according to a 

 Report presented in May, 1879, to tne London Metropolitan 

 Board of Works by Bazalgettes and Keates, as follows : 



With only one circuit used 13' 17 horse-power. 



With two circuits used I7'9i ,, 



With three circuits used 2075 



With four circuits used 23^53 



And for each candle 



With 5 candles i '59 horse-power. 



With 10 candles 1*27 



With 15 candles 1*03 



With 20 candles 0*92 



From these numbers the work required to drive the ma- 

 chines in vacua has been deduced. 



According to the same report, the luminous power of these 

 candles in Carcel lamps is : 



For the naked light 39-8 horse-power. 



For one with frosted glass 27*9 



opaline glass 16-5 



Whence it would follow that the opaline glasses absorb 59 

 per cent., and the frosted glasses 30 per cent, of the emitted 

 light. 



In order to increase the illuminating power of his candles, 

 Jablochkoff has used condensers of large surface, the effect 

 of which is to increase the tension as well as the quantity of 

 the alternating currents. For this purpose he puts a con- 

 ductor from the generator in communication with the homolo- 

 gous armatures of a series of condensers, the other armatures 

 of which correspond separately or collectively with the 

 different candles connected with the generator. Both for 

 quantity and tension the effects are superior to those pro- 



