File off an ounce from the fire-end of a poker. The iron filings
produced are perfectly combustible, as may be proved by sprinkling them
over the flame of a candle. As they descend into the flame they take
fire, each particle burning like a star—producing, in fact, miniature
fireworks. Any iron filings will burn in the same way; but a poker is
the handiest means to prove that while iron, in a solid mass, will not
burn, in small atoms it takes fire readily. It is just for the same
reason that a fire is better lighted with chips than with a log of wood.