A. Yes, but it is necessary in order to obtain good results that boiler and fire-box be in good condition, coal broken to the proper firing size; then, with the hearty and intelligent co-operation of both engineer and fireman, smokeless firing is both economical and practicable.

23.  Q. In what condition should the fire be in order that the best results may be obtained from the combustion of the coal?

A. The fire should be as light as the work being done by the engine will permit, evenly distributed over the grates and free from clinkers.

24.  Q. How should the blower be used?

A. A blower should be used very lightly, being careful not to draw too much air into the fire-box and through the flues, especially when fire is being cleaned or thin on grates.

25.  Q. What is the result of opening the fire-door when the engine is working steam?

A. It will cause a cooling effect in the fire-box and is liable to start the flues leaking.

26.  Q. What is the effect of putting too many scoops of coal on a bright fire?  Is this a waste of fuel?

A. It has the effect of temporarily deadening and cooling the fire, causes emission of quantities of black smoke, as only a limited amount of gas can be burned in a fire-box at a time; all in excess of that amount escapes from the stack and is a waste of fuel.

27.  Q. What effect has the fire upon a scoopful of coal when it is placed in the fire-box?

A. The heat from the fire drives the gases from the coal and they are ignited by the hot flame as they pass over the bright fire; the coke which is left burns where it is.

28.  Q. In what condition should the fire be to consume these gases?

A. A bright white coke fire, almost incandescent.

29.  Q. What is the temperature of the fire when in this condition?

A. It must not be less than 1,800 degrees Fahrenheit to consume the gases liberated from the coal, and it only requires from 750 to 900 degrees Fahrenheit to burn the coke that remains on the grate; as coke burns from the outside, less heat is required to consume it.

30.  Q. How can the fire be maintained in this condition?

A. By adding coal to the fire in small quantities, spreading it over the grate surface and no faster than it is burned.

31.  Q. What is black smoke?  Is it combustible?

A. Black smoke consists of small particles of carbon suspended in the gases of combustion and indicates incomplete combustion.  Black smoke is not combustible, it is like lampblack and cannot be burned after having been produced.  The production of it can be prevented by suitable arrangements and manipulation.

32.  Q. Should the gas not burn in the fire-box, will it burn after it enters the flues?  Why?

A. Gas will not burn only a short distance in the flues of a boiler, as the water absorbs the heat so quickly that the temperature of gas is lowered below the igniting point.