th light, often the companion of
heat. Light travels in straight lines only; electricity can go round a
corner every inch for miles, and, none the worse, yield a brilliant beam
at the end of its journey. Indirectly, therefore, electricity enables us
to conduct either heat or light as if both were flexible pencils of
rays, and subject to but the smallest tolls in their travel.

We have remarked upon such methods as those of the electric welder which
summon intense heat without fire, and we have glanced at the electric
lamps which shine just because combustion is impossible through their
rigid exclusion of air. Then for a moment we paused to look at the
plating baths which have developed themselves into a commanding rivalry
with the blaze of the smelting furnace, with the flame which from time
immemorial has filled the ladle of the founder and moulder. Thus methods
that commenced in dismissing flame end boldly by dispossessing heat
itself. But, it may be said, this usurping electricity usually finds its
source, after all, in combustion under a steam-boiler. True, but mark
the harnessing of Niagara, of the Lachine Rapids near Montreal, of a
thousand streams elsewhere. In the near future motive power of Nature's
giving is to be wasted less and less, and perforce will more and more
exclude heat from the chain of transformations which issue in the
locomotive's flight, in the whirl of factory and mill. Thus in some
degree is allayed the fear, never well grounded, that when the coal
fields of the globe are spent civilization must collapse. As the
electrician hears this foreboding he recalls how much fuel is wasted in
converting heat into electricity. He looks beyond either turbine or
shaft turned by wind or tide, and, remembering that the metal dissolved
in his battery yields at his will its full content of energy, either as
heat or electricity, he asks, Why may not coal or forest tree, which are
but other kinds of fuel, be made to do the same?

One of the earliest uses of light was a means of communicating
intelligence, and to this day the signal lamp and the red fire of the
mariner are as useful as of old. But how much wider is the field of
electricity as it creates the telegraph and the telephone! In the
telegraph we have all that a pencil of light could be were it as long as
an equatorial girdle and as flexible as a silken thread. In the
telephone for nearly two thousand miles the pulsations of the speaker's
voice are not