occasion. The effects produced are magnificent, especially by the
sulphide of calcium and sulphide of zinc. From the disruptive
discharge coil they glow intensely merely by holding them in the hand
and connecting the body to the terminal of the coil.

To whatever results investigations of this kind may lead, their chief
interest lies for the present in the possibilities they offer for the
production of an efficient illuminating device. In no branch of
electric industry is an advance more desired than in the manufacture
of light. Every thinker, when considering the barbarous methods
employed, the deplorable losses incurred in our best systems of light
production, must have asked himself, What is likely to be the light of
the future? Is it to be an incandescent solid, as in the present lamp,
or an incandescent gas, or a phosphorescent body, or something like a
burner, but incomparably more efficient?

There is little chance to perfect a gas burner; not, perhaps, because
human ingenuity has been bent upon that problem for centuries without
a radical departure having been made--though this argument is not
devoid of force-but because in a burner the higher vibrations can
never be reached except by passing through all the low ones. For how
is a flame produced unless by a fall of lifted weights? Such process
cannot be maintained without renewal, and renewal is repeated passing
from low to high vibrations. One way only seems to be open to improve
a burner, and that is by trying to reach higher degrees of
incandescence. Higher incandescence is equivalent to a quicker
vibration; that means more light from the same material, and that,
again, means more economy. In this direction some improvements have
been made, but the progress is hampered by many limitations.
Discarding, then, the burner, there remain the three ways first