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?