or when they are
being started up, care must be taken to prevent oil from flowing and
collecting on the floor of the furnace before it is ignited. In starting
a burner, the atomized fuel may be ignited by a burning wad of oil-soaked
waste held before it on an iron rod. To insure quick ignition, the steam
supply should be cut down. But little practice is required to become an
adept at lighting an oil fire. When ignition has taken place and the
furnace brought to an even heat, the steam should be cut down to the
minimum amount required for atomization. This amount can be determined
from the appearance of the flame. If sufficient steam is not supplied,
particles of burning oil will drop to the furnace floor, giving a
scintillating appearance to the flame. The steam valves should be opened
just sufficiently to overcome this scintillating action.

Air Supply--From the nature of the fuel and the method of burning, the
quantity of air for combustion may be minimized. As with other fuels,
when the amount of air admitted is the minimum which will completely
consume the oil, the results are the best. The excess or deficiency of
air can be judged by the appearance of the stack or by observing the
gases passing through the boiler settings. A perfectly clear stack
indicates excess air, whereas smoke indicates a deficiency. With
properly designed furnaces the best results are secured by running near
the smoking point with a slight haze in the gases. A slight variation in
the air supply will affect the furnace conditions in an oil burning
boiler more than the same variation where coal is used, and for this
reason it is of the utmost importance that flue gas analysis be made
frequently on oil-burning boilers. With the air for combustion properly
regulated by adjustment of any checkerwork or any other device which may
be used, and the dampers carefully set, the flue gas analysis should
show, for good furnace conditions, a percentage of CO_{2} between 13 and
14 per cent, with either no CO or but a trace.

In boiler plant operation it is difficult to regulate the steam supply
to the burners and the damper position to meet sudden and repeated
variations in the load. A device has been patented which automatically
regulates by means of the boiler pressure the pressure of the steam to
the burners, the oil to the burners and the position of the boiler
damper. Such a device has been shown to give good results in plant
operation where hand reg