Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1890-11-16
MESSAGES BY CABLE.
How the News of Europe is Sent
Under the Sea TO America.
NOTHING LIKE WORK ON LAND.
There is No Sounder and the Words Are
Written Out on Paper.
SAMPLES FROM TEE LONG WIRES

The manner in which the cablegrams
printed in The DISPATCH every day are
sent and received over the transatlantic
cables is very different from that in which
kilograms are transmitted across the conti-
nent on land lines. Tho two systems of sub
marine and overland t.leglaphy, although
but two departments OF the one science, and
in many ways closely connected, are ye:
entirely different one frpm the other. The
apparatus, the methods of signalling, and
even the telegraphic characters that form
the alphabet, are altogether dlssimilar, and
the most expert land-lIns operator would be
as much at a loss in I'm attempt to send
message over the cable as would q locomo-
tive engineer.
Instead Of the loud clatter and din and the
incessant clicking of brass saunders, so
familiar to every one as the distinctive char
acteristic OF a telegraph Office, there is in
the cable office almost absolute silence, so
far as the manipulation of the instruments
is concerned. Instead Of the messages being
ratified noisily off the tongue of brass
sounder into the ear Of the operator they are
silently written bv a slender, mysterious
finger on a ribbon of white paper, which
passes quickly before the operators eyes.
A DELICATELY ADJUSTED PEN.
The paper ribbon about half an inch
wide, is unwound from roll and drawn
along by noiseless clocEwork over shelf
like desk in front of the operator. A
delicate glass tube, no thicker than an ordi-
nary needle and crooked like a bent fore
finger, which is suspended between the poles
OF large upright magnet, moves nervously
to the right and left on the ribbon being
drawn beneath it, and traces in thin line
of blue ink characters that look something
like the markings on a barometer chart or
the quotation board of the Gold and Stock
Board.
The instrument, says the New York Sun,
is the Thompson siphon recorder, an elabora-
tion of the Thompson mirror instrument,
once generally used on submarine cables,
with which messages were read by the flash
ing or wavering OF little dot of light on a
graduated scale. In the recorder the prin-
ciple is the same, but the movements of the
fash light are recorded on the paper slip.
On account OF the perfect iRsu lation OF a
submarine cable and for various other
| technical reasons it is only necessary or safe
to use a very small amount of electrical
power to transmit messages through it. About
80 volts is all that is required to transmit q
message under the Atlantic from America
to Europe. A similar force of current on q
land lire woul3 barely carry message from
the postoffice to Yonkers.
THE DELICATE ADJUSTMENT.
II the comparatively Olumsy adjustments
used for land telegraphy were used on the
Atlantic cables, scarcely one word a minute
could be transmitted, while with the recorder
a speed of from fifteen 10 twenty. five words
a minute is regularly maintained. The
mirror, which is still used on some cables,
is the most delicate and perfect telegraph
instrument ever invented. 1t is simply q
small needle suspended in a magnetic coil,
delicate and fragile as feather caught in a
spiders web. The needle is piece of watch
spring three-elghths Of an inch long, sus.
pended bv short thread of cocoon silk and
having small piece of silvered glass affixed
to it with shellac.
The whole thing weighs but one and q
half grains. The instrument is placed in q
dark room, and a ray of light from lamp
is centered through lens on the mirror and
reflected back on to graduated scale. The
currents of electricity sent through the cable
enter the magnetic coil and cause the needle
to be DETECTED from side to side, the motions
being made to form telegraphic characters.
These minute vibrations are read off by an
operator, who calls out each word as he re.
ceives it to copyist, usually in an adjoin.
ing lighted room.
HOW THE PEN WORKS.
The principle of the mirror is, in ths
main, that of the recorder now used on al
the principal cables, but in place of the
small coil large upright magnet is used
| and q modification of the needle arrange
ment is suspended between the two poles
and has a very delicate glass tube, bent like
siphon, attached to it in place of the sill
vered glass. Que end of the siphon rests in
a reservoir of ink, and the other end is ad
justed within hairs breadth of the surface
of the white paper ribbon which is drawn
beneath it. Aniline ink is forced through
the sipkon by an electric process, and as the
tube moves to the right and LETT with the
currents it traces the movements on the
paper ribbon. As the ribbon passes before
the operator, the marks are read upward snG
downward; the upward marks correspond in
a sense to the dots and the downward to the
dashes of the Morse alphabet.
Il Owing to the peculiarities of SPACED let
ters" in the ordinary Morse alphabet, which
cannot be transmitted on the recorder, ar
entirely different combination of characters
called the continental code, is used. I'm.
like the Morse, the dots and dashes of which
are always alike, or should be, unless tn,
operator is a "ham," the cable signals var,
much in proportion to the length of tn,
cable, and from many other causes.
HOW THE LINES LOOK.
The drawings given below are reproduc
tions OF transatlantic cable slips or ribbons
| The messages traced thereon were sent ovel
the cable by which newspaper cable news i.
received from Europe:
>--N