The Romance of Modern Chemistry

HOW FIRE IS MADE air in the tube is compressed by rapidly pushing down the piston, the tinder ignites. A similar apparatus, with a tube, however, of hard wood or ivory, has actually been found in use in Burmah. Among the mechanical methods of producing fire we must not forget to reckon the lens or burning-glass, by which the rays of the sun may be focussed at a point. Combustible material which will not ignite when merely exposed to the sun will at once take fire if brought to the point at which the heat is thus concentrated. The burning-lens was known to the Greeks, and is commonly used by the Chinese. Some readers may remember the story according to which Archimedes, during the siege of Syracuse, set the Roman fleet on fire with the aid of burning-glasses. It is rather a “tali'” story, not con- firmed by the historians, but it serves at least to show that the use of the lens in the production of fire was familiar to the ancient world. All the foregoing methods of obtaining fire are physical or mechanical methods, and it was not till 1805 that an attempt was made to employ a chemical method for the purpose. In that year a certain Frenchman showed that splints of wood coated with sulphur and tipped with a mixture of chlorate of potash and sugar would ignite when brought into contact with sulphuric acid—oil of vitriol, as it is commonly called. The chemical action which takes place spontaneously between the acid, the chlorate of potash, and the sugar is accompanied by the evolution of so much heat that ignition takes place, the sulphur first and then the wood bursting into flame. The first really practical lucifer matches were made in England about 1827. They consisted of wooden splints or sticks of cardboard coated with sulphur, and 121