Year: 1872

Ordinary combustion is the rapid
union of oxygen with some other sub
stance, producing light and heat. When
the union is slow, light does not result,
and the heat is less. This is sometimes
called slow combustion. The point at
which ordinary burning commences is
called the point of ignition, and this
varies greatly in different substances.
1t is obvious that the greater the affini-
ty of any substance for oxygen, the
more readily it will burn !. e., unite
rapidly with oxygen. There are some
substances that will do this either at
the ordinary temperature, or only lit
tie above it.


Among the substances which have a
special liking for oxygen is oil that has
been recently made. This, when poured
upon some tinderlike substance, as cot
ton or wool, is not unlikely, in its avid
ity for oxygen, if there is free supply,
to take in SO much as to raise the tenn
persture and set the tinder on fire. And
this is one example of a phenomenon,
not uncommon, which is called 'spon-
taneous combution." Cotton waste
which has been used for cleaning
machinery, and which becomes saturated
with oil, is therefore, dangerous when
lying around, especially if allowed to
accumulate in any considerable quantity.
Cloths also saturated with oil or covered
with varnish and turpentIne, and silks,
too, have sometimes proved to be in
fammable. Many metals, also, have q
great affinity for oxygen. In turning
and working these, much oil is used.
If, therefore, the turnings and filings,
hus saturated with oil, are allowed to
accumulate, what more natural than
that the oil should become fired, and
the fire communicate to any other COM
bustible substance that may be near?


Bituminous coal often contains much
of substance known as the sulphuret
of iron, which has a great affinity for
oxygen. The slate and refuse coal, La
BILE to be thrown together and remain in
piles, especially abound in this material,
which sometimes spontaneously ignites.
A fire once occurred in the royal ship
yard, at Copenhagen, from this cause,
which consumed sixteen hundred tons
of coal and fourteen hundred houses.
The liability of some varieties OF btu
minous coal to spontaneous ignition
seriously affects its value, as it renders
the storage and transportation, especi-
ally in vessels, dangerous. Newly
burned charcoal, too, will sometimes
generate heat, sufficient to set it on fire.
And in Stiunaan's Journal Of Science
may be found detailed a number of well
authenticated instances, in which hard
wood ashes generated heat enough to
set wood on fire, though no fresh adj
ditions had been made to the ashes for
weeks. One of the instances occurred
in the cellar of President Lord of OAR
mouth College, where heap of twenty
five bushels of ashes, which had been
two years in accumulating, became suf-
ficiently heated throughout to fire a
stick thrust into them. The danger was
discovered by the smell. as of burnt
ashes, which attracted attention
throughout the house, and WAS finally
traced to this pile in the cellar. The
most probable explanation of cases like
this seems to be that the ashes contain
ed finely puly erized charcoal enough to
ignite spontaneously, on the same prin-
ciple that ordinary charcoal, or btu
minous coal, sometimes does. Too
much care can not be taken to guard
against danger from all such sources as
these