CHAPTER XV.
294. Why does paper ignite more readily than wood?
Because its texture is less dense than that of wood; its particles are therefore more readily heated and decomposed.
295. But if articles of loose texture are bad conductors of heat, why do they so easily ignite?
The fact that they are bad conductors assists their ignition. The heat which would pass from particle to particle of the dense substance of iron, and be conducted away, accumulates in the interspaces of paper, and ignites it.
296. Why does wood ignite less readily than paper?
Because its substance is denser than that of paper; it therefore requires a higher degree of heat to inflame its substance.
297. Why does wood, when ignited, burn longer than paper?
Because, being a denser substance, it submits a larger number of particles, within a given space, to the action of the heat, and the formation of gases.
298. Why do we, in lighting a fire, first lay in paper, then wood, and lastly coals?