ts of heat into the water at a given temperature in a given time;
two square feet twice as many, and three, three times as many, and so
on. Put a cover upon the pot, and seal it tight, leave an orifice for
the steam, and that is a steam boiler with all its mysteries.

The old-fashioned, plain cylinder boiler is a plain cylindrical pot
over the fire. If enough plain cylinder boilers presenting the
requisite number of square feet of absorbing surface are put into a
cotton mill, experience has shown that they will make a yard of cotton
cloth about as cheaply as tubular boilers. If this is so, why do not
all put them in? Because it is the crudest and most expensive form of
boiler when its enormous area of ground, brickwork, and its fittings
are considered. Not all have the money or the room for them. To
produce space, the area is drawn in sidewise and lengthwise, but we
must have the necessary amount of square feet of absorbing surface,
consequently the boiler is doubled up, so to speak, and we have a
"flue boiler." We draw in sidewise and lengthwise once more and double
up the surface again, and that is a "tubular boiler." That includes
all the "mystery" on that subject.

Now, we find among the mills, just as I imagine we should upon the
railroads, that the almost universal tendency is to put in too small
boilers and furnaces. To skimp at boilers is to spend at the coal
yard. Small boilers mean heavy and over-deep fires, and rapid
destruction of apparatus. In sugar houses you will see this frequently
illustrated, and will find 16 inch fires upon their grates.

We have found that, as we could persuade mill owners to put in more
boilers and extend their furnaces, so that coal could be burned
moderately and time for combustion afforded, we often saved as high as
1,000 tons in a yearly consumption of 4,000.

Now, when the ordinary locomotive sends particles of coal into the
cars in which I am riding, I do not think it would be unfair criticism
to say that the process of combustion was not properly carried out.
When we see dense volumes of gas emitted from the stack, it is evident
that a portion of the hard dollars which were paid for the coal are
being uselessly thrown into the air; and it will be well to remember
that only a little of the unburnt gas is visible to the eye.

One point I wish to make is this: We find, as I have said, that as we
spread out with boilers and furnaces in the mills, so that we can take
matters