danger
of hitching or becoming displaced, on the same principle as a thing
sliding on a concave groove. The carriage was set in motion by a
mere push, and, having received, this impetus, rolled with us down
an inclined plane into a tunnel, which forms the entrance to the
railroad. This tunnel is four hundred yards long (I believe), and
will be lighted by gas. At the end of it we emerged from darkness,
and, the ground becoming level, we stopped. There is another tunnel
parallel with this, only much wider and longer, for it extends from
the place which we had now reached, and where the steam-carriages
start, and which is quite out of Liverpool, the whole way under the
town, to the docks. This tunnel is for wagons and other heavy
carriages; and as the engines which are to draw the trains along
the railroad do not enter these tunnels, there is a large building
at this entrance which is to be inhabited by steam-engines of a
stationary turn of mind, and different constitution from the
traveling ones, which are to propel the trains through the tunnels
to the terminus in the town, without going 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 small 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 c