"Blind; yes. Not one of them has seen the light of day since he entered
the mine, and some of them have been there for more than a dozen years.
Living always in the dark, they have lost the power to see."

"Go on. What were you going to say?"

"Why, that those mules represent an investment of twenty or twenty-five
thousand dollars, all absolutely needless. Their use involves also a
wholly unnecessary expense for stablemen, feed, and general care, while
the yearly deaths among them add heavily to the profit and loss account,
on the loss side. Not one of those mules is needed in the mine. The work
they do can be better done at one-tenth the cost--yes, it can be done at
no cost at all; while if the mules are brought out and sold, they will
bring from twenty to twenty-five thousand dollars."

"Go on. Explain. What do the mules do, and how is their work to be done
without them?"

"They do just two things; they haul coal to the bottom of the inclined
shaft, where it must be reloaded--at wholly unnecessary expense--in
order to be hauled by machinery up the incline to the surface. Half the
time they are employed in hauling water. The mine, you must understand,
declines from the foot of the shaft to the end of the main heading. The
very lowest level of all is there, where I propose to put in a
ventilating shaft, with a fan; all the water flows to that point,
flooding it. Under the antediluvian methods in use in this mine, all
this water must be pumped into leaky cars and hauled by mules to the
bottom of the the sloping shaft, whence it is drawn up by the engine,
spilling half of it before it reaches the surface. Now, when I sink that
ventilating shaft out there on the prairie, I must have an engine to
turn the fan. Very well, I've got it. Among the junk that Captain Hallam
bought when the war ended and the river navy went out of commission,
there are parts of many little steam engines. I've busied myself at
night in measuring these and fitting part of one to parts of another.
The result is that I have made an engine out of this rubbish, which will
not only drive the ventilating fan, but will also pump all the water out
of the mine."

"But will not the mules be needed for hauling coal to the bottom of the
shaft?"

"Not at all, if you are willing to spend a little money in an
improvement--say a fourth or a third of what the mules will bring in the
market--or considerably less than it costs to feed and curry them for a
y