The coal and the large sticks cannot be kindled with a match, but the
paper and shavings can, and these in burning will heat the large
sticks until they take fire and in turn kindle the coal.
43. Spontaneous Combustion. We often hear of fires "starting
themselves," and sometimes the statement is true. If a pile of oily
rags is allowed to stand for a time, the oily matter will begin to
combine slowly with oxygen and as a result will give off heat. The
heat thus given off is at first insufficient to kindle a fire; but as
the heat is retained and accumulated, the temperature rises, and
finally the kindling point is reached and the whole mass bursts into
flames. For safety's sake, all oily cloths should be burned or kept in
metal vessels.
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