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

THE GREAT CROSSING OVER THE RIVER ELBE. 659
is effected by lashing a strong spar, by its middle, to the top of
the pile, by a piece of chain, and a party of five men at each
end man this spar, capstan manner. The screwing is easily
accomplished in a stiff clay, sandy, or light gravelly soil, in five
minutes. Four iron rope or rod iron jointed guys should then
be permanently attached to screw piles of the three-feet pattern,
planted obliquely in the ground. Each pile has a short wrought
iron link for the attachment of the guy, and each guy has a
tightening screw to regulate its tension.
THE GREAT CROSSING OVER THE RIVER ELBE.
The most remarkable crossing on masts, in Europe, is that
over the river Elbe near Hamburg. I have frequently examined
that crossing, and as it is regarded by the European telegraphers as a great achievement in the art, I will give the details of
it as furnished by Mr, Gerk, the engineer of the line. The
principal arm of the Elbe is about 1,200 feet wide, and is navigated by sailing vessels of moderate tonnage.
For rivers averaging 1,500 feet in breadth Mr. Gerk advises the use of masts strongly and substantially built, and
from 30 to 40 feet higher than the highest masts of the
vessels which have to pass below. This is necessary to allow
for a deflection of one fiftieth in the wire, which, when of the
very best description, can be strained no tighter, without great
risk of fracture by storms, or by the weight of icicles in
northern climates.
Five masts, such as I will proceed to describe, were erected
in 1848 for the crossing of both arms of the Elbe.
Each mast penetrates 10 feet in the ground, and is there
wedged down between strong cross beams, and the whole
covered with heavy stones or concrete. About 16 feet from
the end of each beam a pile is driven deeply and obliquely
into the earth for the attachment of the stays, which are iron
rods, one inch diameter below, three fourths of an inch in the
middle, and half an inch at top. These stays lead from the
piles to the top of the lower mast, where they are attached to
a wrought iron collar with four eye-bolts and rings. At 9 feet
from the ground each stay is provided with a straining screw
by which it is tightened to the required degree.
The masts described and figured by Mr. Gerk are 180 feet
high, in several pieces bound together by wrought iron rings,
2 feet in diameter at the ground, tapering to 4 inches at the
top. The first set of cross-trees is at 70 feet from the ground.
Four beams, each of 36 feet long, are laid cross-tree fashion at the