The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

344 THE FRENCH RAILWAY ELECTRIC TELEGRAPH.
ordinary office apparatus, but in its construction it is the same.
In case its use becomes necessary, by a train, the line wire is
cut and connected through the instrument, and thus, means of
communication is speedily formed with an office to the right or to
the left, as the case may be. The arrangement is simple and
easy to be operated. The contrivance exhibits much ingenuity, particularly in the simplicity of its manipulation.
BREGUET S IMPROVEMENT.
In regard to the clockwork indicated by fig. 4, Mr. Breguet
has made a very valuable improvement, as will be seen by
fig. 8.
Fig. 8. In the description given of fig. 1,
ai ^^ it was stated that by pressing the
button d, the respective instruments would be brought in unison
/f ^ - I ~^of action by making some 13 revorri ir u lutions and stops. Mr. Breguet's
plan economizes time, and more
speedily accomplishes the end desired.
l, v la By pressing lightly on the Lutton
d, the needle is made to move one
1,/T\~.\ single notch, by pressing it strongly
it passes instantly to the cross, or
zero, of the index plate. The butmY =tton, placed at the top of the ap-; nm' ~ paratus, instead of moving a little
r Z strip pressing on the armature, as
in fig. 4, it is placed at the extremity of a long vertical rod, as seen in fig. 8. The spiral
spring h holds up the axis, x Y bears, together with the escapement anchor z, a little horizontal strip b c, which presses
against the extremity of the rod d a b. When the button d is
pressed upon lightly, the strip c b, as they make the axis x Y,
and the escapement anchor z to turn at each pressure, a tooth
of the wheel L escapes, and the indicating needle advances one
division. If, on the contrary, the strip c d is pressed forcibly,
it is lowered, and lets the tooth m' pass beyond the escapementwheel L, the wheel then being entirely disengaged, rapidly
turns, bearing with it the needle. The rotation stops promptly,
because the axis L bears a point v, which hits against a projection a of the rod d b.
At the moment when the rod d b is raised a little, the pro