Q. Give an example of spontaneous combustion.
A. Goods packed in a warehouse will often catch fire of themselves; especially such goods as cotton, flax, hemp, rags, &c.
Q. Why do such goods sometimes catch fire of themselves?
A. Because they are piled together in very great masses in a damp state or place.
Q. Why does this produce spontaneous combustion?
A. The damp produces decay or the decomposition of the goods, and the great heat of the piled-up mass makes the decaying goods ferment.
Q. How does this fermentation produce combustion?
A. During fermentation, carbonic acid gas is given off by the goods,—a slow combustion ensues,—till at length the whole pile bursts into flame.
Q. Why is the heat of a large mass of goods greater than that of a smaller quantity?
A. Because compression squeezes out heat, as water is squeezed from a sponge; and as the goods of a large pile are greatly compressed, much of their latent heat is squeezed out.