and (we make the assertion with the confidence born of long experience) a
large number of destructive explosions have been directly caused by
introducing the feed water into boilers at the wrong point.

On the location and construction of the feed depends to some extent the
economical working of a boiler, and, to a great extent, especially with
certain types of boilers, its safety, durability, and freedom from a
variety of defects, such as leaky seams, fractured plates, and others of
a similar kind. And it is unfortunately true that the type of boiler
which from its nature is most severely affected by mal-construction, such
as we are now speaking of, is the very one which is the oftenest subject
to it. We are speaking now more particularly of the plain cylinder
boiler, of which there are many in use throughout the country.

Plain cylinder boilers are, as a rule, provided with mud drums located
near the back end. As a rule, also, these boilers are set in pairs over a
single furnace, and the mud drum extends across beneath, and is connected
to both, and one end projects through the setting wall at the side. Our
illustrations show a typical arrangement of this kind. Fig. 1 shows a
transverse section of the boilers and setting, while Fig. 2 shows a
longitudinal section of the same. It is a favorite method to connect the
feed pipe, F, to the end of the mud drum which projects through the wall,
and here the feed water is introduced, whether hot or cold; and there is
really not so much difference after all between the two, for no matter
_how_ effective a heater may be, the temperature to which it can raise
water passing through is quite low compared with the temperature of the
water in the boiler due to a steam pressure of say eighty pounds per
square inch. The difference in the effect produced by feeding hot or cold
water at the wrong place is one of degree, not of kind.