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

MANIPULATION OF THE CHAPPE TELEGRAPH. 41
each. The axis of the large lever also carries a divisor of 8
notches; but while the divisors of the two hands are fixed in
relation to the axis which traverses them, said divisor of the
large lever is fixed upon the axis and turns with it. When
we wish to hold the regulator on account of high wind, or for
other cause, we place a kind of bolt fixed in the post to enter
one of these notches, and this bolt stops all movements of the
regulator.
As the indicator ought always to remain motionless, when
the regulator is moved after a signal is made, the spring
above mentioned always holds the tooth of the hand fixed
in the notch of the divisor when said hand has been placed
in such a way that the operator is obliged, when he wishes to
change the position of an indicator, to draw the hand toward
himself in order to disengage the tooth, and to let go of the
hand when the tooth has arrived opposite the new notch in
which the tooth is to be fixed. From these facts it will be
seen that the mechanism of the Chappe telegraph is a model
of simplicity and precision. It fulfills the conditions of rapidity, clearness, and variety in execution.
Let us suppose that the telegraph is at rest in the position
represented in fig. 13, which position is called the vertical closed,
and that the operator enters his office in the morning; he commences by applying his eye alternately to first one, and then
the other of his neighboring telegraph stations, to see if either of
them are giving a signal, and, in the meantime, he arranges
on his desk, pen, ink, and record-book.
As soon as he sees one of the two stations move, he draws the
bolt which holds the large axis at rest, and puts one hand upon
the upper handle of the great crank, and then looks at the signal which has been formed.
If the regulator is to be carried to the right oblique, or
left oblique, which is indispensable, he pushes the upper extremity of the handle to the right or left, aiding the movement at the same time by pushing the lower extremity with his
leg, at the same time he puts his other hand upon the small
lower crank 1' n in order to commence moving the indicator;
the regulator being once set in motion, he lets go the upper
handle in order to take hold of the handle l' n.", and move the
second indicator, thus the signal being formed, he stops it on
the oblique which belongs to it. He thus looks through his
telescope to the station whence the signal came, to see if said
signal has been carried to the horizontal or to the vertical.
If it has been carried, he knows it to be correct, and accordingly records it as he sees it horizontal or vertical in the square