ve trains run in and out
between 9 and 10 A.M., and an equal number between 4 and 5 P.M. Again,
at the Clapham Junction, near London, about 700 trains pass or stop
daily; and though to the casual observer the succession of trains coming
and going, running and stopping, coupling and shunting, appears a scene
of inextricable confusion and danger, the whole is clearly intelligible
to the signalmen in their boxes, who work the trains in and out with
extraordinary precision and regularity.

The inside of a signal-box reminds one of a pianoforte on a large scale,
the lever-handles corresponding with the keys of the instrument; and, to
an uninstructed person, to work the one would be as difficult as to play
a tune on the other. The signal-box outside Cannon Street Station
contains 67 lever-handles, by means of which the signalmen are enabled at
the same moment to communicate with the drivers of all the engines on the
line within an area of 800 yards. They direct by signs, which are quite
as intelligible as words, the drivers of the trains starting from inside
the station, as well as those of the trains arriving from outside. By
pulling a lever-handle, a distant signal, perhaps out of sight, is set
some hundred yards off, which the approaching driver--reading it quickly
as he comes along--at once interprets, and stops or advances as the
signal may direct.

The precision and accuracy of the signal-machinery employed at important
stations and junctions have of late years been much improved by an
ingenious contrivance, by means of which the setting of the signal
prepares the road for the coming train. When the signal is set at
"Danger," the points are at the same time worked, and the road is
"locked" against it; and when at "Safety," the road is open,--the signal
and the points exactly corresponding.

The Electric Telegraph has also been found a valuable auxiliary in
ensuring the safe working of large railway traffics. Though the
locomotive may run at 60 miles an hour, electricity, when at its fastest,
travels at the rate of 288,000 miles a second, and is therefore always
able to herald the coming train. The electric telegraph may, indeed, be
regarded as the nervous system of the railway. By its means the whole
line is kept throbbing with intelligence. The method of working the
electric signals varies on different lines; but the usual practice is, to
divide a line into so many lengths, each protected by its
signal-stat