e circumference of a carbon wheel which rotates underneath the
point. The light is developed at the place of contact of rod and
wheel. One of the last steps, though I am informed not quite the
last, in the improvement of regulators is this: The 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 pole a hollow cone of copper, and by ingeniously discharging
a small jet of 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.

I might go on to other inventions, achieved or projected. Indeed,
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 public lighting, I strongly lean to the opinion that the
electric light will at no distant day triumph over gas. I am not so
sure that it will do so in our private houses. 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
realisation of the idea, of causing the carbon rods to burn away like
a candle. It is needless 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. 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