certain determined points on the line; for example, at the top of
heavy grades. For this purpose it has only been necessary to add to
the apparatus that we have just described an electro-magnet, E,
connected electrically with a fixed contact located on the line. When
the current passes, that is to say, at the moment the circuit is
closed by the passage of a train, the armature, A, is attracted, and
the pencil marks a point on the cardboard disk. This modification of
the apparatus has not as yet been practically applied.

_Electrical Corresponding Apparatus._--The object of these apparatus
is to quickly transmit to a distance a certain number of phrases that
have been prepared in advance. The Company of the North employs two
kinds of correspondence apparatus--the Guggemos and the annunciator
apparatus.

1. _The Guggemos Apparatus._--This apparatus serves at once as a
manipulator and receiver, and consists of an inner movement surmounted
by a dial, over the face of which moves an index hand. Around the
circumference of the dial there is arranged a series of circular
cases, C, containing the messages to be received, and similar
triangular cases, containing the messages to be forwarded, radiating
from the center of the dial. Between each of these there is a button,
b.

Fig. 13 represents the interior of an apparatus for twenty messages.
It consists of a key-board, M, an electro-magnet, B, a clock-work
movement, Q, an escapement, s, and an interrupter, F G.

When one of the buttons, b, is pressed, one of the levers of the
key-board arrangement touches the disk, M, which is insulated from the