obably the most general of
such shortcomings is the fixed idea in the heads of the operatives that
boilers run above their rated capacity are operating under a state of
strain and that by operating at less than their rated capacity the most
economical service is assured, whereas, by determining what a boiler
will do, it may be found that the most economical rating under the
conditions of the plant will be considerably in excess of the builder's
rating. Such ideas can be dislodged only by demonstrating to the
operatives what maximum load the boilers can carry, showing how the
economy will vary with the load and the determining of the economical
load for the individual plant in question.

2nd. Stokers. With stoker-fired boilers, it is essential that the
operators know the limitations of their stokers as determined by their
individual installation. A thorough understanding of the requirements of
efficient handling must be insisted upon. The operatives must realize
that smokeless stacks are not necessarily the indication of good
combustion for, as has been pointed out, absolute smokelessness is
oftentimes secured at an enormous loss in efficiency through excess air.

Another feature in stoker-fired plants is in the cleaning of fires. It
must be impressed upon the operatives that before the fires are cleaned
they should be put into condition for such cleaning. If this cleaning is
done at a definite time, regardless of whether the fires are in the best
condition for cleaning, there will be a great loss of good fuel with the
ashes.

3rd. It is necessary that in each individual plant there be a basis on
which to judge the cleanliness of a boiler. From the operative's
standpoint, it is probably more necessary that there be a thorough
understanding of the relation between scale and tube difficulties than
between scale and efficiency. It is, of course, impossible to keep
boilers absolutely free from scale at all times, but experience in each
individual plant determines the limit to which scale can be allowed to
form before tube difficulties will begin or a perceptible falling off in
efficiency will take place. With such a limit of scale formation fixed,
the operatives should be impressed with the danger of allowing it to be
exceeded.

4th. The operatives should be instructed as to the losses resulting from
excess air due to leaks in the setting and as to losses in efficiency
and capacity due to the by-passing of gases through