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

TELEGRAPH CROSSINGS OVER RIVERS
CHAPTER XLVI.
Telegraph Crossings in Europe-The Great Crossing over the River ElbeWide Spans of Wire on the Continent-River Crossings in America-Description of the Great Mast on the Ohio River-Suspension of the Wire
over the Masts-A Western Frontier Telegraph Crossing.
TELEGRAPH CROSSINGS IN EUROPE.
THE telegraph lines in Europe do not traverse very large
rivers, compared with those of America. The Elbe, the Neimen,
and the Dwina, are the widest crossed by the wires on
masts. The telegraphs on that continent have, therefore, had
but little experience in crossing rivers with the lines erected in
the air. As a general thing, throughout the world, the use of
masts has been abandoned, and submarine crossings adopted
in their stead. In order, however, that the telegraph may be
prepared to meet any emergency, I will explain in sufficient
detail, the manner of using masts for long stretches over swamps
or rivers.
In regard to the crossings of streams, the opinion entertained
in Europe is, that rivers under twelve hundred feet in breadth,
are to be crossed in this manner, in all cases where it is
practicable, having reference to the height of the masts of the
vessels passing under the line at the highest level in the rainy
season.
It being impracticable to give precise rules applicable to each
case. it will best fulfil the object of these pages to give an exact
description of some remarkable river crossings effected in this
manner in Europe.
The following are the details of the construction of the telegraph masts at Norwich.
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