15 
mits the subdivision of the light by placing several lamps 
in the course of one electric circuit. It is also stated that 
the construction of the candle may be varied ; and, among 
the forms described, is one in which the carbons, instead of 
being contained in a cartridge case, are separated by a par- 
tition of kaolin or other similar insulating material. 
I have thought it well to describe, as nearly as possible 
in the words of the inventor, the electric candle, which is 
now the subject of so much attention in its application to 
electric lighting ; so that its relation to what follows may be 
more clearly perceived. A remarkable peculiarity of the 
direct current in electric lighting is that of its consuming 
the positive carbon at twice the rate of the negative one, 
and while the negative carbon is a pointed cone, like that of 
a pencil, the positive pole takes the form of a hollow cavity 
or crater. 
M. Jablochkoff’s early experiments seem to have been 
made with the direct current, and hence his carbons are 
described as being of unequal thickness in order that the 
positive and negative carbons of the candle might be evenly 
consumed. When the alternating current is used for pro- 
ducing electric light both carbons are of the same thickness, 
and are consumed at an equal rate, and both points termi- 
nate in regular cones. This property of the alternating 
current, besides other advantages, always maintains the 
luminous point in the focus of any optical apparatus used 
in connection with it, that is, when the carbons are placed 
end to end, as I had occasion to point out in a former paper 
read before the Society in 1873, on an Electro Magnetic 
Induction Machine for producing alternating currents. 
M. Jabloclikoff, in the course of his experiments, would 
appear to have met with some difficulties in adapting the 
direct or continuous current to a system of lighting with 
his electric candles, and now uses the alternating current 
for this purpose. The candle has also been simplified by 
