purpose to a large extent by sugar refiners, who thus decolorize their
dark brown sirups; in the manufacture of glucose and saccharums for
brewers' use, the concentrated solutions have to be filtered through
layers of animal charcoal in order that the resulting product may be
freed from color. The decolorizing power of animal charcoal can be
easily tested by any brewer, by causing a little dark colored wort to
filter through a layer of this material; after passing through once or
twice, the color will entirely disappear, or at all events be greatly
reduced in intensity. Animal charcoal also absorbs gases with great
avidity, and on this account it is utilized as a powerful disinfectant,
for when once putrefactive gases are absorbed by it, they undergo a
gradual oxidation, and are rendered innocuous, in the same way animal
charcoal is a valuable agent for purifying water, for by filtering the
most impure water through a bed of animal charcoal nearly the whole of
the organic impurities will be completely removed.

Lamp-black is the name given to those varieties of carbon which are
deposited when hydrocarbons are burned with an insufficient supply of
oxygen; thus the smoke and soot emitted into our atmosphere from our
furnaces and fireplaces are composed of comparatively pure carbon.

Coal is an impure form of carbon derived from the gradual oxidation and
destruction of vegetable matters by natural causes; thus wood first
changes into a peaty substance, and subsequently into a body called
lignite, which again in its turn becomes converted into the different
varieties of coal; these changes, which have resulted in the
accumulation of vast beds of coal in the crust of the earth, have been
going on for ages. There are very many different kinds of coal; some are
rich in hydrogen, and are therefore well adapted for making illuminating
gas, while others, such as anthracite, are very rich in carbon,