then pounding it down smooth to prevent any leaking. This done, you can
screw the plug back into its place.

If you should have two plugs, as soon as you have melted out one replace
it with the new one, and refill the other at your earliest convenience.
By the time you have replaced a fusible plug a few times in a hot boiler
you will conclude it is better to keep water over your crown sheet.

LEAKY FLUES

What makes flues leak? I asked this question once, and the answer was
that the flues were not large enough to fill up the hole in flue sheet.
This struck me as being funny at first, but on second thought I
concluded it was about correct. Flues may leak from several causes, but
usually it can be traced to the carelessness of some one. You may have
noticed before this that I am inclined to blame a great many things to
carelessness. Well, by the time you have run an engine a year or two
you will conclude that I am not unjust in my suspicions. I do not blame
engineers for everything, but I do say that they are responsible for a
great many things which they endeavor to shift on to the manufacturer.
If the flues in a new boiler leak, it is evident that they were slighted
by the boiler-maker; but should they run a season or part of a season
before leaking, then it would indicate that the boiler-maker did his
duty, but the engineer did not do his. He has been building too hot a
fire to begin with, or has, been letting his fire door stand open; or he
may have overtaxed his boiler; or else he has been blowing out his
boiler when too hot; or has at some time blown out with some fire in
firebox. Now, any one of these things, repeated a few times, will make
the best of them leak. You have been advised already not to do these
things, and if you do them, or any one of them, I want to know what