iting by passing his fingers over the letters.

Edison's next important work was the adaptation of the electric light
for domestic illumination. At the beginning of the century the Cornish
philosopher, Humphrey Davy, had discovered that the electric current
produced a brilliant arch or 'arc' of light when passed between two
charcoal points drawn a little apart, and that it heated a fine rod of
charcoal or a metal wire to incandescence--that is to say, a glowing
condition. A great variety of arc lamps were afterwards introduced; and
Mr. Staite, on or about the year 1844-5, invented an incandescent lamp
in which the current passed through a slender stick of carbon, enclosed
in a vacuum bulb of glass. Faraday discovered that electricity could
be generated by the relative motion of a magnet and a coil of wire, and
hence the dynamo-electric generator, or 'dynamo,' was ere long invented
and improved.

In 1878 the boulevards of Paris were lit by the arc lamps of Jablochkoff
during the season of the Exhibition, and the display excited a
widespread interest in the new mode of illumination. It was too
brilliant for domestic use, however, and, as the lamps were connected
one after another in the same circuit like pearls upon a string, the
breakage of one would interrupt the current and extinguish them all
but for special precautions. In short, the electric light was not yet
'subdivided.'

Edison, in common with others, turned his attention to the subject, and
took up the neglected incandescent lamp. He improved it by reducing the
rod of carbon to a mere filament of charcoal, having a comparatively
high resistance and resembling a wire in its elasticity, without being
so liable to fuse under the intense heat of the current. This he moulded
into a loop, and mounted inside a pear-shaped bulb of glass. The bulb
was then exhausted of its air to prevent the oxidation of the carbon,
and the whole hermetically sealed. When a sufficient current was passed
through the filament, it glowed with a dazzling lustre. It was not too
bright or powerful for a room; it produced little heat, and absolutely
no fumes. Moreover, it could be connected not in but across the main
circuit of the current, and hence, if one should break, the others would
continue glowing. Edison, in short, had 'subdivided' the electric light.

In October, 1878, he telegraphed the news to London and Paris, where,
owing to his great reputation, it caused an immediate panic in