The Romance of Modern Chemistry

CHAPTER X CHEMICAL CHANGES WHICH PRODUCE LIGHT AND HEAT TO the popular mind a chemical laboratory is suggestive of explosions—reactions which result in the very evident production of light and heat, and sound into the bargain. But it is not necessary to visit a chemical laboratory in order to observe chemical changes which produce light and heat, for we are all chemists to some extent, at our own firesides. When we strike a match or light a fire we make a chemical experiment, but the <£ Red Flower ” is so familiar to us that we miss the meaning and the marvel of it. The making of fire is one of the oldest chemical achievements of the human race, and in our modern world the part played by combustion is of enormous importance. A little thought will show it is on those chemical changes which produce light and heat that we depend for a great many of our modern social conveniences. Where does the power come from which drives our motor cars ? Why, from the combustion of petrol. Further, when a man stands on the footplate of a “ Flying Scotchman,” or in the engine-room of the Mauretania, he begins to understand what wonders in the way of locomotion we owe to the combustion of coal. “ Ah, yes ! ” some reader may say ; “ but we are going in for electricity nowadays, are we not ? We are lighting 106