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

552 TELEGRAPH INSULATION.
moist earth, commensurate with their conductibility, there can
be no doubt as to their efficiency in preserving the line from
much, if not all of the annoyance resulting from atmospheric
electricity.
THE BAVARIAN INSULATOR.
Fig. 56 Fig. 56 represents the insulator used
_{ on the Bavarian lines. It is a glass bell,
fitted and cemented to an iron arm,
which is screwed to the post as seenin,M| f! ~ 7 i the figure. To the top of the glass is
cemented, in small openings, two castiron projections, through which are two
holes. The line wire is laid on the top
of the glass between the iron projections,
and then two wedges are driven through
the holes in opposite directions, which
securely binds the wire and prevents it
from moving upon the insulator. Theiron arms are fastened on the sides of
the post. Sometimes one bolt, with
nuts at each end, fasten an arm on each side, but the metallic
connection between the two arms might prove to be disadvantageous to the working of the line. In damp weather cross
currents will pass from one wire to the other.
THE HOLLAND INSULATOR.
Fig. 57. On the line from Amsterdam
to the Hague, in Holland, is
used the insulator represented
by fig. 57. It is made of glass,
with an iron bolt cemented at
^^.= fIB Wthe top and fastened to a cross-;i — libeam by a nut screwed to the
upper end of the bolt. To the
interior is cemented an iron pendant for supporting the wire.
This insulator has proved its
usefulness.
THE BADEN INSULATOR.
The insulator represented by fig. 58 is used on the Baden
lines, extending from Manheim on the Rhine, via Carlsruhe to
Kehl and Strasbourg. The insulator is composed of earthenware, cemented on the top of the pole by plaster-of-paris, as