In order to fire an engine properly the fireman need not necessarily know anything about the theory of combustion. He may have learned to apply the principles without knowing the reason for so doing. In fact many first rate firemen do not understand anything about these principles. There are, however, certain fundamental facts that should be borne in mind when endeavouring to explain to firemen the necessity of doing certain things to get proper results. To produce heat in a locomotive firebox three conditions are necessary—and only three.

First. There must be a supply of coal.

Second. There must be a plentiful supply of air.

Third. The air and the coal must be brought together at a temperature at which they will burn.

Although through long experience a good fireman acts in a very skilful manner, it is certain that an intelligent knowledge of the theory of combustion will secure better results. Every driver and fireman should pay great attention to the study of combustion and endeavour to appreciate what is taking place in the firebox, tubes and smokebox.

Every fireman is aware that the air passing through the damper doors and firebars causes rapid combustion of the heated fuel, that gases are given off which are burned by mixing with the air that comes through the firehole door. He is also aware that in this way heat is produced which is passed to the water in the boiler through the firebox sheets and through the tubes, and that the heating of the water produces steam.

Now a man who wishes to become a good engineman will not rest here. He will seek to understand what is taking place when coal is shovelled into the firebox. It is in the interest of fuel economy that supervising officers should help the staff to grasp the essential facts of the theory of combustion. We will endeavour to show what combustion is, and what goes on in the firebox, and the best methods to be adopted by the fireman to get the best results.