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

DESCRIPTION OF THE RECEIVING INSTRUMENT. 335
which is stopped by an anchor. A soft iron armature, moveable in front of an electro-magnet, communicates an oscillatory
movement to that anchor, which, at every movement, lets a
tooth of the wheel pass. The exterior dial bears letters, signs,
or figures, and the needle may stop before any one of them.
The whole is contained in a case, in which the dial alone is
exposed to view. The model of the apparatus illustrated and
explained in this chapter, is the same as that used in the telegraphic bureaux of France. The same system, a little modified,
I noticed on the Belgian railways. It has proved to be of the
greatest utility in the service, and every railway has in perfect
organization this system of telegraph, having an office or
bureau at every station.
DESCRIPTION OF THE RECEIVING INSTRUMENT.
The receiver of this telegraph will be seen in fig. 1; it is inclosed within its cover. The dial has 26 divisions; the upper
is a cross, and the other divisions are the alphabet. The first
25 numbers are placed on the interior of the dial-plate. The
needle, I in', is made of mica or steel, nicely balanced, and
fixed frictionally on the axis of an escapement wheel. At the
upper part, on the right hand, is a little dial, of which the axis
a acts with the recoil spring of the armature. The two screws
or binding posts, A A', serve to fix the wires by which the current enters and leaves. At the place of the letter At in the
alphabet is a square, b, by means of which the clock-work is
wound up. When the current is not passing, the needle may
be advanced, by pressing on the button or thumb-key d, situated at the upper part of the case.
In fig. 2 is represented a side view of the vertical projection
of the apparatus. Fig. 3 is a horizontal projection, and fig. 4
is a perspective view of the armature, the anchor, and the
escapement wheel. In all the figures, the same objects are represented by the same letters. The clock-work movement is comprised between two copper plates, B c and D E. The little barrel,
Mr, contains a large spring, and its axis corresponds to the exterior square represented at b, in fig. 1.
The axis of the upper wheel, F G I-, bears an index needle,
H H', and the escapement wheel, concealed in fig. 2 by the
armature-rod, but visible at iL, in fig. 4. The electro magnet
N, figs. 2 and 3, is placed above the clock movement, on a copper plate, D D'. It is held by two vertical posts, and a copper
strip, w w'. The two soft iron rods of the electro magnet, held
together by a third rod, K, are independent of the spools, and
can be moved by means of the screw-adjuster L L'. In order