39. Q. What will cause the engine to tear holes in the fire?

A. Working hard or slipping when the dampers are open and the door

closed, or too thin a fire.

40. Q. Name the various adjustable appliances in the front end by which

the draft may be regulated.

A. The exhaust nozzle, the diaphragm and the draft pipes or petticoat

pipe.

41. Q. What object is there in having the exhaust steam go through the

stack?

A. To create a draft through the tubes and fire-box.