is provided with a handle or lever in position to be conveniently
handled by fireman while seated in cab. This valve regulates the flow of
oil desired to reach the fire.

49. Q. When shutting out fire which valve should be closed first? Why?

A. The safety valve. To allow the oil in pipes to be consumed and to see
that this valve is in working order.

50. Q. Should safety valve fail to shut off the flow of oil in such
cases would it be safe to rely on the firing valve to shut off the fire?

A. No. The main valve should then be closed.

51. Q. Should the firing valve be depended upon to shut off the fire at
any time? Why?

A. No. From constant use they are frequently leaking and the trouble is
not detected while in use, and again there is always danger of the
handle being moved by workmen or others about the cab.

52. Q. What is a heater box?

A. It is an apparatus having two passages, one for steam passing from
boiler to heater pipes in tank and another passage for oil from tank
before it is delivered to burner. In this manner the oil before reaching
the burner is heated much higher than the temperature of that contained
in tank.

53. Q. In the event of the heater pipes or connections becoming