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

140 EARLY ELECTRIC TELEGRAPHS.
are those which would probably be found suitable in a working
machine; but it will be understood that the length in the
machine may be a hundred or a thousand miles, and is limited
to five feet in the model, merely for convenience. Thirty copper
wires extend from end to end of the chest, and are kept apart
from each other. At one end (which, for distinction's sake,
we shall call the south end) they are fastened to a horizontal
line of wooden keys, precisely similar to those of a pianoforte;
at the other, or north end, they terminate close to thirty small
apertures, equally distributed in six rows of five each, over a
screen of three feet square, which forms the end of the chest.
Under these apertures on the outside, are painted, in black
paint, upon a white ground, the twenty-six letters of the alphabet, with the necessary points, the colon, semicolon, and
full point, and an asterisk, to denote the termination of a word.
The letters occupy spaces about an inch square. The wooden
keys, at the other end, have also the letters of the alphabet,
Fig. 3.
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