needle, and better able to actuate a mechanism. It became the
foundation of the recording instrument of Samuel Morse, the father
of the telegraph in America. The Morse, or, rather, Morse and Vail
instrument, actually marks the signals in "dots" and "dashes" on a
ribbon of moving paper. Figure 49 represents the Morse instrument,
in which an electromagnet M attracts an iron armature A when a
current passes through its bobbins, and by means of a lever L
connected with the armature raises the edge of a small disc out of
an ink-pot I against the surface of a travelling slip of paper P,
and marks a dot or dash upon it as the case may be. The rest of
the apparatus consists of details and accessories for its action
and adjustment, together with the sending-key K, which is used in
asking for repetitions of the words, if necessary.

A permanent record of the message is of course convenient,
nevertheless the operators prefer to "read" the signals by the
ear, rather than the eye, and, to the annoyance of Morse, would
listen to the click of the marking disc rather than decipher the
marks on the paper. Consequently Alfred Vail, the collaborator of
Morse, who really invented the Morse code, produced a modification
of the recording instrument working solely for the ear. The
"sounder," as it is called, has largely driven the "printer" from
the field. This neat little instrument is shown in figure 50,
where M is the electromagnet, and A is the armature which chatters
up and down between two metal stops, as the current is made and
broken by the sending-key, and the operator listening to the
sounds interprets the message letter by letter and word by word.

The motion of the armature in both of these instruments takes a
sensible time, but Alexander Bain, of Thurso, by trade a