The Romance of Modern Chemistry

HOW FIRE IS MADE millions are turned out daily, and that for each million of matches about one pound of phosphorus is required. The forty or fifty tons of phosphorus annually used in England for tipping matches are obtained from bones, which contain a large proportion of phosphate of lime. The high rate at which matches are turned out has become possible only by the introduction of ingenious labour-saving machinery, and no one who has not been through a match factory can realise how much is done in this direction. Another curious device for the production of fire was brought out by Döbereiner in 1823. The lamp known by his name is no longer used, but it was based on a very interesting principle, and therefore deserves consideration. We have seen that hydrogen is a combustible gas, and if we bring a light close to a nozzle from which hydrogen is escaping, it will take fire; that is, the hydrogen com- bines with the oxygen of the air at a high temperature, forming water vapour. At ordinary temperatures, on the other hand, hydrogen and oxygen are generally in- different to each other. There is, however, one substance which is able to promote the union of hydrogen and oxygen, even under these conditions, namely spongy platinum—that is, platinum in a very finely-divided con- dition. Platinum is usually a compact white metal, heavier than gold, but by special chemical treatment it can be obtained as a dark, porous powder, and in this condition it is extremely active. If instead of bringing a flame to the nozzle from which hydrogen is issuing, we hold a little spongy platinum in the gas, the metal begins to glow and presently the hydrogen catches fire. A very pretty instance this of what is known as “ cata- lytic” action, a term denoting the curious effect which 125