saying that more than half the engineers of threshing engines today
depend on the "blowing out" process to clean their boilers. I don't
intend to tell you to do anything without giving my reasons. We will
take a hot boiler, for instance; say, 50 pounds steam. We will, of
course, take out the fire. It is not supposed that anyone will attempt
to blow out the water with any fire in the firebox. We will, after
removing the fire, open the blow-off valve, which will be found at the
bottom or lowest water point. The water is forced out very rapidly with
this pressure, and the last thing that comes out is the steam. This
steam keeps the entire boiler hot till everything is blown out, and the
result is that all the dirt, sediment and lime is baked solid on the
tubes and side of firebox. But you say you know enough to not blow off
at 50 pounds pressure. Well, we will say 5 pounds, then. You will admit
that the boiler is not cold by any means, even at only 5 pounds, and if
you know enough not to blow off at 50 pounds, you certainly know that at
5 pounds pressure the damage is not entirely avoided. As long as the
iron is hot, the dirt will dry out quickly, and by the time the boiler
is cold enough to force cold water through it safely, the mud is dry and
adheres closely to the iron. Some of the foreign matter will be blown
out, but you will find it a difficult matter to wash out what sticks to
the hot iron.

I am aware that some engineers claim that the boiler should be blown out
at about 5 pounds or I0 pounds pressure, but I believe in taking the
common sense view. They will advise you to blow out at a low pressure,
and then, as soon as the boiler is cool enough, to wash it thoroughly.

Now, if you must wait till the boiler is cool before washing, why not
let it cool with the water in it? Then, when you let the water out,
your work is easy, and the moment you begin to force water through it,