and you can rest
assured that it is reliable. This little operation I want you to
perform every day you run an engine. It will prevent you from thinking
you have water. I don't want you to think so. I intend that you shall
know it. You remember we said, if you know you have water, you are
safe, and every one around you will be safe.

Now here is something I want you to remember. Never be guilty of going
to your engine in the morning and building a fire simply because you see
water in the glass. We could give you the names of a score of men who
have ruined their engines by doing this very thing. You, as a matter of
course, want to know why this can do any harm. It could not, if the
water in the boiler was as high as it shows in the glass, but it is not
always there, and that is what causes the trouble. Well, if it showed
in the glass, why was it not there? You probably have lived long enough
in the world to know that there are a great many boys in it, and it
seems to be second nature with them to turn everything on an engine that
is possible to turn. All glass gauge cocks are fitted with a small hand
wheel. The small boy sees this about the first thing and he begins to
turn it, and he generally turns as long as it turns easy, and when it
stops he will try the other one, and when it stops he has done the
mischief, by shutting the water off from the boiler, and all the water
that was in the glass remains there. You may have stopped work with an
ordinary gauge of water, and as water expands when heated, it also
contracts when it becomes cool. Water will also simmer away, if there
is any fire left in the fire box, especially if there should be any vent
or leak in the boiler, and the water may by morning have dropped to as
much as an inch below the crown sheet. You approach the engine and on
looking at the glass, see two or three inches of water. Should you
start a fire without investigating any further, you will have done the
damage, while if you try the gauge cocks first you will discover that
some one has tampered with the engine. The boy did the mischief through
no malicious motives, but we regret to say that there are people in this
world who are mean enough to do this very thing, and not stop at what
the boy did unconsciously, but after shutting the water in the gauge for
the purpose of deceiving you, they then go to the blow-off cock and let
enough water out to insure a dry crown sheet. While I detes