ent to the test, not only of scientific
but also of practical verification, and the probability is that all
electric lighting stations in the twentieth century will contain not
only dynamos of one type for the supply of light, but also direct
current generators for transmitting power in all directions over the
same cables.

The glow lamp having no carbon filament, but setting up a bright light
with only a fraction of the resistance presented by carbon, would, if
perfected, render electric lighting by far the cheapest as well as the
best method of illumination. Tentative work has indicated a high
degree of probability that success will be achieved, and the glowing
bulb is at any rate a possibility of the future which it will be well
to reckon with.

In reference to the conversion of heat into electricity without the
intervention of machinery to provide motion, and thus to cause
magnetic fields to cross one another, very little promise has yet been
shown of any fundamental principle upon which a practical apparatus of
the kind could be based. The electrician who works at this problem
has to begin almost _de novo_, and his task is an immensely difficult
one, although on every ground of analogy success certainly looks
possible. In the meantime, as has already been indicated, the steam
turbine and dynamo combined, working practically as a single machine
for the generation of electricity, offers practically the nearest
approach to direct conversion which is yet well in sight.

CHAPTER XI.

WARFARE.

The last notable war of the nineteenth century has falsified the
anticipations of nearly all the makers of small arms. The magazine
rifle was held to be so perfect in its trajectory, and in the rapidity
with which it could discharge its convenient store of cartridges in
succession, that the bayonet charge had been put outside of the region
of possibility in warfare. Those who reasoned thus were forgetting, to
a large extent, that while small arms have been improving so also has
artillery, and that a bayonet charge covered by a demoralising fire of
field-pieces, mortars, and quick-firing artillery is a very different
thing from one in which the assailants alone are the targets exposed
to fire. Given that two opposing armies are possessed of weapons of
about equal capacity for striking from a distance, they may do one
another a great deal of harm without comi