THE ELECTRIC LIGHT. 
27 
of wire, each of which when under the inductive influence is 
tapped by two brushes at a tangent to a circular commutator 
placed on the shaft, and carrying off the electricity in one con- 
tinuous direction. It is also made in three sizes, costing 
respectively £70, £100, and £300, giving the light of 2,000, 
6,000, and 15,000 candles. 
Hitherto the subject has been considered in regard to single 
lights ; but an important advance consists in securing the divisi- 
bility of the current so as to produce a number of lights instead 
of one. This object has been sought for for the last twenty 
years, but only practically solved by the Lontin and the Jabloch- 
koff- Gramme systems. Both these work with currents not con- 
tinuous, but in alternate directions. Indeed, the “ candle ” of 
M. Jablochkoff requires this as an essential condition to produce 
the equal combustion of the two parallel carbons. The Gramme 
machines have been therefore so modified as to meet this necessity. 
Mons. Lontin works on another line. He has designed two 
machines instead of one. The former is termed the generator, 
the latter the divider. 
The generator consists of a horse- shoe electro-magnet, be- 
tween the poles of which rotates a coil formed in a star-like 
shape, of which the projecting arms are wound with wire. A series 
of these stars is arranged obliquely along the rotating shaft, 
so as to obviate any abrupt break in the inductive action. Two 
rubbing contacts collect the positive and negative currents, carry- 
ing them through the fixed magnet and so to the second machine. 
This, the “ divider,” has a shaft carrying a series of larger 
stars with more radial electro-magnets, into which the currents 
from the generator are passed, so that they remain in a state of 
magnetic saturation. 
Each star revolves in a wrought-iron cylinder, studded on 
its inner surface with short induction coils corresponding to the 
radii of the revolving star- wheel. These are coupled together 
so that their positive and negative poles are presented alter- 
nately to those in rotation. The result is a number of currents 
alternate in direction and equal in number to half the rotating 
spokes. The alternating current from each ring is collected 
separately on the exterior, and conveyed to a frame where the 
various elementary currents may be coupled in any desired 
number of circuits. The usual apparatus has twenty-four discs, 
which, by being coupled in pairs, produce twelve circuits, and 
can supply twelve separate lights, or can be all devoted to a 
single lamp. 
The number of lights produced by one of these engines, which 
has a total illuminating power of 1 2,000 standard candles, at the 
Western Railway in Paris, varies from six to twelve. But as 
many as thirty have been supplied from a similar machine at the 
Lyons Railway Station. 
