out of
their houses themselves. The length of the tunnel parallel to the one we
passed through is (I believe) two thousand two hundred yards. I wonder
if you are understanding one word I am saying all this while? We were
introduced to the little engine which was to drag us along the rails.
She (for they make these curious little fire horses all mares) consisted
of a boiler, a stove, a platform, a bench, and behind the bench a barrel
containing enough water to prevent her being thirsty for fifteen
miles,--the whole machine not bigger than a common fire engine. She goes
upon two wheels, which are her feet, and are moved by bright steel legs
called pistons; these are propelled by steam, and in proportion as more
steam is applied to the upper extremities (the hip-joints, I suppose) of
these pistons, the faster they move the wheels; and when it is desirable
to diminish the speed, the steam, which unless suffered to escape would
burst the boiler, evaporates through a safety valve into the air. The
reins, bit, and bridle of this wonderful beast, is a small steel handle,
which applies or withdraws the steam from its legs or pistons, so that a
child might manage it.

"The coals, which are its oats, were under the bench, and there was a
small glass tube affixed to the boiler, with water in it, which indicates
by its fullness or emptiness when the creature wants water, which is
immediately conveyed to it from its reservoirs. There is a chimney to
the stove, but as they burn coke there is none of the dreadful black
smoke which accompanies the progress of a steam vessel. This snorting
little animal, which I felt rather inclined to pat, was then harnessed to
our carriage, and Mr. Stephenson having taken me on the bench of the
engine with him, we started at about ten miles an hour. The steam horse
being ill adapted for going up and down hill, the road was kept at a
certain level, and appeared sometimes to sink below the surface of the
earth and sometimes to rise above it. Almost at starting it was cut
through the solid rock, which formed a wall on either side of it, about
sixty feet high. You can't imagine how strange it seemed to be
journeying on thus, without any visible cause of progress other than the
magical machine, with its flying white breath and rhythmical, unvarying
pace, between these rocky walls, which are already clothed with moss and
ferns and grasses; and when I reflected that these great masses of stone
had