s is nice for you to know, and it may start you on a
higher course, it will not make you handle your engine any better, but
it may convince you that there is something to learn.

Suppose we give you a little touch of rules, and formula in boiler
making.

For instance you want to know the percent of strength of single riveted
and double riveted as compared to solid iron. Some very simple rules,
or formula, are applicable.

Find the percent of strength to the solid iron in a single-riveted seam,
1/4 inch plate, 5/8 inch rivet, pitched or spaced 2 inch centers. First
reduce all to decimal form, as it simplifies the calculation; 1/4=.25
and 5/8 inch rivets will require 11/16 inch hole, this hole is supposed
to be filled by the rivet, after driving, consequently this diameter is
used in the calculation, 11/16 inches=.6875.

First find the percent of strength of the sheet.

P-D
-----
The formula is P = percent.

P = the pitch, D = the diameter of the rivet hole, percent =
percent of strength of the solid iron.

2 -.6875
--------
Substituting values, 2 = .66.
Now of course you understand all about that, but it is Greek to some
people.

So you see I have no apologies to make for following out my plain
comprehensive talk, have not confused you, or lead you to believe that
it requires a great amount of study to become an engineer. I mean a
practical engineer, not a mechanical engineer. I just touch mechanical
engineering to show you that that is something else. If you are made of
the proper stuff you can get enough out of this little book to make you
as good an engineer as ever pulled a throttle on a traction engine. But
this is no novel. Go back and read it again, and ever time you read it
you will find something you had not noticed before.

INDEX
-----

PART FIRST PAGE
Tinkering Engineers . . . . . . . . . . . 5
PART SECOND
Water Supply . . . . . . . . . . . . . . 31
PART THIRD
What a Good Injector Ought to Do . . . 45
The Blower . . . . . . . . . . . . . . . 49
A Good Fireman . . . . . . . . . . . . 51
Wood . . . . . . . . . . . . . . . . . . 56
Why Grates Burn Out . . . . . . . . . . 57
PART FOUR
Scale . . . . . . . . . . . . . . . . . 65
Clean Flues . . . . . .