The sun. [volume] (New York [N.Y.]) 1833-1916, 1879-03-03

$50 miles OF cable covered with a close en-
velope OF brass tape, in locality much In
tested with tercdoes.
But the submarine cables have to endure
other dangers than those from tercdoes and
they are 80 many that IL is no wonder they
last for only ten OF fifteen years, while It is
remarkable that communication by means
OF them is not oftcncr interrupted. A cable
is singularly weak against attack, for II
hurt at any one point, the whole Is disabled.
Icebcrgs grating on the sea bottom have
been known TO cut the cables. Ships anchors
frequently foul and damage them, though
no instance of sunken ships settling down
on them has so far been reported. An ex-
traordnary complication was that which
occurred in the Persian Gulf, whore a whale
got entangled and shared to death In the
cable. The Brazilian cable from Para to
Cayenne has been again and again inter-
rupted by fish bites; the sawllsh has an
noyed one of the East Indian cables; and
big turtles have crushed that from Havana
to Key West.
The damages to cables which necesstato
their being lifted for repairs are ordinarily
due to one OF six causes-abrasion, anchors,
teredoes, broken conductors, deterioration
of the Insulating properties OF the core, and
lightning. The abrasion Ia brought about,
obviously enough, by the fcstooning OF tho
cable between two prominences on the sea
bottom, and the action of tides and currents
In deep water, or waves in shallow water.
The first cause may be, and OF late has been,
obvlatcd by careful soundings. The anchors
OF ships and fishing smacks frequently
a o,,,o. hn Az "a on hn ~
Newfoundland. and II Ia hard to ward
against the injury. All that can be done is
TO shcathe tho cable heavily, or TO avoid
fishing grounds in laying 1t, and TO persuade
| the fishermen 10 be more careful about drop
ping their anchors. Broken conductors are
due usually TO excessive strain on the cable,
but earthquakes have been known. es-
| pecially on the west coast Of South America,
| To rupture the cables by the upswelling Of
the ocean bed Lightning has damaged one
or two Mediterranean cables, but there is no
instance Of it's doing injury to any cable pro-
vided with an efficient lightning protector.
A review OF what has been done for the de-
velopment OF ocean telegraphing within tho
last twenty years, since the laying Of the
first experimental cable, which was COM
pletcd on the 9Th OF August, 1858, will be full
| OF interest. Ocean tclegraphing has revolu-
tionized the methods of commerce and made
us all citizens of the world daily cognizant
| OF what chiefly occupies the thoughts OF the
| peoples IN all quarters OF the globe, OF the
course OF their markets, and the movements
in their politics. And all this has been done
| within twenty years.
Will the young men who are now antici-
pating the casting Of their maiden vote next
autumn, and who have been born since the
time when no messages were sent under the
sea. and the arrival of n European steamer
was an event of great public interest. star
tie the readers of The SUN in the twentieth
century with something as wonderful as the
instantaneous passage OF news from Lon
don to New York was TO the newspaper
| renders of 1882