Non-Inflammable Material.

Place a coin under a cotton handkerchief and ask someone to press a burning cigarette on the cloth stretched over the coin. You need not be afraid of scorching the material, because only a harmless speck of ash will be left.

The experiment shows that the metal of the coin is a much better conductor of heat than the cotton fabric. On rapid pressure the heat of the burning cigarette is immediately conducted away by the coin. There is only enough heat to cause a small rise in temperature in the coin, and the cotton does not reach a high enough temperature to burn.