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

588 SUBTERRANEAN TELEGRAPHS.
While at Berlin, in 1S54, through the kindness of the administration of the telegraphs, I was present at the examination
of the subterranean wires then being substituted by the pole
lines. These wires had been laid under the gutters along the
curbstones of the sidewalks. The leaden covering or pipe
had been in several places eaten away by the acids of the
earth, originating, no doubt, from the slops conducted from the
houses into the streets. The gutta-percha insulation had been
destroyed, and on bending it would fall to pieces, leaving the
copper conducting wire exposed. It was the opinion of those
in authority that the gutta-percha had been improperly manufactured, and that the leaden covering had not been placed
around it with sufficient care to give the necessary protection.
About the same time Russia established a subterranean line
of two wires from St. Petersburg to Moscow, along the railway.
Like the Prussian lines, they failed from time to time, and the
government was compelled to abandon the underground wires
and erect another on poles. The effect on the subterranean
wires was found to be the same as was discovered in Prussia.
Besides, the retardation of the electric current was sensibly
felt between St. Petersburg and Moscow, a distance of some
four hundred miles.
In the city of St. Petersburg and for the telegraph to Cronstadt, some twenty miles long, the wires are laid in the earth,
with extraordinary care and protection from the salines of the
earth. During my visits to Russia in 1854-'57, I never
heard of any complaint against the working of the lines laid
through the cities.
In Denmark the first lines were laid in the same manner
precisely as the Prussian lines, and like results were experienced there. In 1854, the line across the island of Zealand, from
Copenhagen to Corsor, was placed upon poles. It was during
my visit to Copenhagen, in the summer of 1854, that I observed the retardation of the voltaic current on underground
lines, which had been made known by Prof. Faraday. There
were, therefore, two obstacles in the way of successfully working the subterranean lines, namely, the non-insulation of the
wires and the retardation of the electric current when being
transmitted from station to station, the philosophy of which is
considered elsewhere in this book.
In Paris, the subterranean lines insulated with gutta-percha
and lead were at an early day abandoned. By authorization
of the Emperor, I was permitted, in 1854, to examine the details of the telegraphs in France, and I was informed that the
subterranean lines had been unsuccessful. Subsequently, and