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

392 THE HOUSE PRINTING TELEGRAPH.
perfect accuracy, and many of the instruments have operated
foi years with but little repair. [ have recently seen one of
them that had been used to so great an extent, that the
fingers of the operator had worn away the ivory on the keys.
The main constituents of his telegraph are, the composing
machine, the printing machine, a compound axial magnet, a
manual power which sets the two machines in motion, and a
letter-wheel or tell-tale, from which messages can be read,
should the printing machine get out of order.
THE COMPOSING AND PRINTING APPARATUS.
A composing and printing machine are both required at
every station; the printing apparatus is entirely distinct from
the circuit, but all the composing machines are included in
and form part of it: the circuit commences in the voltaic
Fig. 1.
battery of one station, passes along the conductor to another
station, through the coil of the axial magnet to an insulated
iron frame of the composing machine, thence to a circuit
wheel revolving in this frame; it then enters a spring that
rubs on the edge of this circuit wheel, and has a connection