I have here a most
intense heat, produced by the burning of hydrogen in contact with the
oxygen; but there is as yet very little light--not for want of heat, but
for want of particles which can retain their solid state; but when I hold
this piece of lime in the flame of the hydrogen as it burns in the oxygen,
see how it glows! This is the glorious lime-light, which rivals the
voltaic-light, and which is almost equal to sunlight. I have here a piece
of carbon or charcoal, which will burn and give us light exactly in the
same manner as if it were burnt as part of a candle. The heat that is in
the flame of a candle decomposes the vapour of the wax, and sets free the
carbon particles--they rise up heated and glowing as this now glows, and
then enter into the air. But the particles when burnt never pass off from
a candle in the form of carbon. They go off into the air as a perfectly
invisible substance, about which we shall know hereafter.
Is it not beautiful to think that such a process is going on, and that
such a dirty thing as charcoal can become so incandescent? You see it
comes to this--that all bright flames contain these solid particles; all
things that burn and produce solid particles, either during the time they
are burning, as in the candle, or immediately after being burnt, as in the
case of the gunpowder and iron-filings,--all these things give us this
glorious and beautiful light.
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