Evening star. [volume] (Washington, D.C.) 1854-1972, 1873-12-29
IErial and Underground Telegraph
Wirea.

rRoBIEN FOR THE POSTAL TELEGRAPH.
Editor Star. The successful experiments OF
instsntapeously lighting the street lamps OF
street by electric agency are hailed by
ell who have suffered from the dark
ness of corporation moonlight nights." But
they have, on the other hand, revived the
objections to the disagreement OF ali our streets
by Grial lines of wire suspended on telegraph
poles. From year to year these wires will come
in greater conflict with the stately rows of shade
trees which grace our streets. The leading tel
egraph companies are even now frequently puz-
zled where TO place the poles. Many still thinly
settled streets, but partially planted with grown
trees, permit them. however, TO jump over from
one side of the street to the other and back
again, or TO turn In other streets, because the
foliage of a line of healthy growing trees de-
stroys the Insulation and interferes with the
working of the lines, even in calm weather. and
more so when the air stirs. Citizens and au-
thorities consider IL as utterly inadmiSsible TO
curtail the symmetrical development of the
trees by the process of thinning out or cutting
down for the necessities of the wires.
But the remedy is at hand by n resort 70 I'M
derground wires within the limits of the city.
Extensive lines Of underground wires were laid
through Prussia As far back as lS43 but they
had TO he abandoned, and 4 am indebted TO Of
fetal information on the whole subject from
Col. Me gdam, the director general OF the impe-
rial telegraphy in Berlin, obtained through the
kindness OF Baron Schloez yer, the German am
bassador. The unfavorable results obtained
twenty i've years ago were not attributable TO
the system, as interested parties will have IL,
but rather to the lack OF experience on the
qualities of the isolatng material, to the then
very imperfect machines for the manufacture
of isolated wires, and to the undue hurry with
which the work on extensive lines was pushed.
These old lines consisted of gutta percha coated
copper wires, which were simply buried m the
ground. The gutta percha Of that period was
defective, full of bubbles, and the wire was thus
imperfectly covered. External protection being
wanting, the gutta percha, which Is practically
indesructble under water, but readily decom
poses when exposed to the air or in contact with
the earth, was destroyed by chemical action,
by rats, by spades, and even primarily by care
less handling during the transportation and
laying of the wire. The insulation, in conse-
quence, was of no account.
At the present time, mechanical progress
footing on former experience and proitlng by
the experiments for the manufacture OF sub
marine cables, has overcome all the former
objections to subterranean lines, and has proved
the adaptabiity OF the cable by the establish
ment of permanent subterranean lines in and
between many European cities, and, among
others, the German fortresses of the Rhine.
The difficulty of insulating the wire belongs TO
past time. Copper wire is now c0ncentTically
coated with three layers of gutts perchs. united
by an intermediate glutinous isOlating eompo-
siton, "ChatteTdou compound" The insulated
wires intended TO be combined into a cable are
then united and spun over with carefully tarred
hemp, so as TO nentral:ze the destructive india
ence of the earth on the gutta percha. Next
comes tissue OF iron wire, securing the cable
against injury by mechanical causes, and an
outer protecting heavy coat of asphaltum guards
the wire against corrosion. A most careful
examination OF the wires with highly perfected
Instruments, especially by Siemens' method,
serves 10 detect the slightest defects causing
Losses of currents and vouches for unexceptiOnal
material Gables laid twenty years ago,
taken up in Cologne and other places and found
intact.
The retardation of the current, and speed OF
transmission, caused by the SO called stl,i
charge, which subterranean wires take to a
much greater degree than AERIAL wires, cannot
come in account for the comparatively shor;
space within a city, and facts have proved that
the working with Morse's and similar apparatus
is not lmpaire ed for such limited distances. The
difficulty OF repairing injuries has also been
urged against the underground wires, but the
experience Of the German service shows th al
whilst the original investment comes high. the
running expenses are found to be quite trit ing
Test boxes sunk under the pavement OF the
sidewalks serve TO trace any Irregularities
Experiments are now in progress in Prussia
extending under ground lines over thousands OF
miles, where the cable is alternately brought in
communication with the battery ana then with
the earth, or where galvanic currents of oppo
site direction are used for telegraphing pur-
poses. The difficulties of the static charge are
therepy reduced tn minimum and the - -.
ty of Transmission Is restored
1t cannot be expected that the cheaper rrial
INES Will be entirely supplsnted by the more
costly underground lines, since the Increased
expense involved would tend to materially re-
come TO be the nervous system Of the nation
and should most speedily be pushed throughout
all its extremities and ramih atoms, long be-
fore railroads and steamships, these Quasi
blood-yessels of the nation, have reached them
But rhv should not the General Post Office de-
partment, instead of buying nj, the watered
siock Oh the present telegraph lines, as naS
been proposed, take this predestined telegram
OF the future In hand, and establish an under
ground line between the leading cities of the
mon winch could be relied on during and
after atmospheric revolutions, or other occa-
sions when the existing cheaper lines are out of
working order? 1t is well known that the ex-
pansion OF the arisI wires during the summer
months causes them to hang slack, and during
gales to make them liable to touch each Other
and intertwine; further that heavy coatings of
ice during sudden changes of Temperature in
winter are apt, when followed by gale, to bring
whole lines down by dead weight, and finally
that the destructive power of heavy gales have
at several periods brought down whole sections
OF the most substantial rrial lines by unearth-
ing or breaking OFF the poles, SCATTERING the in
eulators and entangliDg or tearing the wires
thus causing an interruption of communication
Tor days and weeks-perhaps at q most inop-
perfume time,
Shall not this progressive country, in which
telegraphy has attained an unreasonable
prominence, take a leading part in obtaining
an Independence of communication from ali
accidents; and where is there a better oppOr-
tunity than in postal underground telegraph
along the leading airline railroads, to commence
with moderate appropriation 20 finish the sec
ton between Washington and Boston?
ADOLF CLUss.