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

536 TELEGRAPH INSULATION.
to be substituted in their place. The earthenware insulator
has proved to be the most substantial and best in every respect
for the purposes of insulation.
AMERICAN INSULATORS.
There is a greater variety of insulators upon the American
telegraphs than is to be found on the lines elsewhere in the
world. The enterprise, from its commencement on the Western
continent in 1844, has been in the charge of "many men of
many minds," and each has been ambitious to excel the others.
This commendable spirit has been productive of much good.
Besides this circumstance attending the erection of the lines,
different sections of America have required an insulator pecu.
liarly adapted to their special wants. On the other hand, however, there have been devised many kinds of insulators for
special sections of the service which have proved destructive
to practical telegraphing.
The first insulator used in America was the cloth, saturated
with gum-lac, wound around the wire at the post contact.
This was on the experimental line, constructed in 1843-'44,
between Washington and Baltimore, under the direction of
Professor Morse. Copper wires were used, and a cross board
was fastened at the top of the pole. A small notch was cut
in the top edge of the board, and the wire, covered with the
saturated gum-lac cloth, was laid in the notch. Over this was
nailed a board, serving as a roof, so that the rain could not
have access to the wire contact on the perpendicular edge of
the cross-board.
Various plans were suggested for the proper and better insulation of the wires. The horn used for lightning rods was
tried and abandoned. Finally the glass was determined upon
as the only reliable means of effecting the great desideratum.
The question was then as to the form of the glass. On this
the opinion of telegraphers are still at variance. Every new
man that comes into power seems to aim for a novel form of
insulation. This singular infatuation among telegraphers I
Fig. 16. Fig. 17. Fig. 18.