1306 coal was so generally used in
London that a petition was sent to parliament to have the use of it
suppressed on the ground that it was a nuisance. Coal was used in
Belgium, however, about 1200. There is a tradition that a blacksmith
first used it in Liege as fuel. It was first used for manufacturing
purposes about 1713.

Coal is found laid down in great veins, varying in thickness, in various
parts of the world in the upper strata of the Paleozoic period. The age
in which it was formed is called by geologists the Carboniferous
(coal-bearing) age.

Before going on to account for the deposits of coal, let us stop a
moment and consider what it is. Chemists tell us that coal is chiefly
constructed of carbon, compounded with oxygen, hydrogen, and nitrogen.
There are many varieties, but all may be classified under two general
headings--bituminous and anthracite. Bituminous coal contains a large
amount of a tarry substance, a kind of mineral pitch or bitumen, which
burns with a brilliant flame and a black sooty smoke, exceedingly rich
in carbon. Anthracite coal is hard and stone-like in its texture,
burning with scarcely any flame and no smoke. It produces a fire of
intense heat when it is once ignited. There is another form of coal
called cannel coal, which is a corruption of "candle coal," so called
because a piece of this kind of coal when ignited will burn like a match
or pine knot and give light like a candle. This is the richest of all
the coal deposits in gases that are set free by heat, and for this
reason is extensively used in the manufacture of what is commonly
called coal gas. England produces a large amount of cannel coal, as well
as another variety of bituminous coal, which latter, however, does not
burn with such a black smoke as the coal found in the Ohio valley and
the Western States of America. East of the Alleghany Mountains there is
a region of anthracite coal that is very extensively worked and finds
great favor in all parts of the country as fuel for domestic heating,
especially on account of its great cleanliness.

All of the coal beds have a common origin, and the difference in the
quality of coal found in different parts of the country is due to many
circumstances, some of which have never been explained. There is
indisputable proof, however, that all coal beds are of vegetable origin.
Geologists tell us that these coal beds were formed during an age before
the earth had cooled down to the temp