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

426 THE MORSE TELEGRAPH APPARATUSES.
the blank rilln is thoe brass cylinder, and the blank openings to
the outer circl3 the metallic forms of the letter j, and the
shaded portion of the circle represents the insulating substance,
covering the whole surface of the cylinder, except where the
letter-forms project from the interior. Every letter and parts
of each letter are in metallic connection with the brass cylinder.
At each end of the cylinder is a brass head, with its metallic
journal, and the journal or arbor turns upon its centre in a
brass standard, 17, secured to the vertical frame. To this
standard is soldered the copper wire N, connected with the
negative pole of the battery. There are together thirty-seven
letters and numerals upon the cylinder. and made to correspond
Fig. 5.
Li3 j
1'~-:.i/- l ^ = 6l _ -
Fig CE. -'
FigJ 6.
Fig 6.