The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1890-11-29
HOW MESSAGES ARE CALLED.
No Sounders Used - Signals Dineren
From Land Telegraphy.
New York 6un.


From Land Telegraphy.
New York Sun.
The manner in which messages are sent
and received over the transatlantic cables
between this country and Europe is very
different from that in which kilograms are
transmitted ACROSS the continent on land
lines. The two systems Of submarine and
overland telegraphy, although but two de-
partments of the one science. and in many
ways closely connected. are yet entirely
different one from the other. The appa-
ratus. the methods of signalling. and even
the telegraphic characters that form the
alphabet, are altogether dissimilar, and the
most expert land-line operator would Be a
much at . LOSE in an attempt 10 send mes
sage over the cable a. would locomotive
engineer.
Instead Of the loud clatter and din and
the tncessant clicking of brass saunders. so
familiar 10 everv one % the distinctive
characteristic Of Z telegraph Office, there il
in the cable office almost absolute silence,
mente u concerned. Instead Of the mes
seRes being ratified noisily of the tongue Of
brass sounder into the ear of the opera
tor, they are silently written BY slender,
mysterious finger on Q ribbon of
wplte paper which passes quickly
before the operators eyes. Tho paper
ribbon, about halt an inch wide, 10
unwound from roll and drawn along BY
noiseless clockwork over = shelf-ltke desk
In front OF tho operator. A delicate glass
tube, no thicker than an ordinary needle
and crooked like bent foretinger, which is
suspended between the poles Of large ND.
right magnet, moves nervously 70 the
right and left on the ribbon being drawn
beneath 1t. and traces in q thin line of blue
hat lfnnk AZ nis4r, iExx,t h.
markings on . barometer chart or the
quotation board Of the gold and stock
board.
The instrument il the Thompson siphon
recorder, an elaboration of the Thompson
mirror instrument, once generally used on
submarine cables. with which messages
were read BY the flashing or Wavering of q
little dot of light on graduated scale. In
the recorder the principle = the same, but
the movements Of the fash light are re-
corded on tho paper slip. On account Of
the perfect insulation of . submarine cable
and for various other technical reasons it
is only necessary or safe to use avery small
sages through it. About thirty volts Is I'LL
that Is required to transmit message
under the Atlantic from America 10 Eu-
rope. A similar force OF current on land
line would barely carry q message from
the postoffice to Yonkers.
II the comparatively clumsy instruments
used for land topography were used on the
Atlantic cables scarcely one word Z minute
could be transmitted, while with the re-
corder speed of from fifteen 10 twenty.
i've words minute IL regularly maintained.
The mirror, which is still used on some
cables, IL the most delicate and perfect tele-
graph instrument ever invented. 1t is
small needle suspended in . magnetic
coil, delicate and fragile IS feather caught
watch spring. thres-sights OF an inch long.
OF cocoon silk and having q
small piece OF siivered glass affixed to 1t
with sbelisc. The who're thing weighs but
one and . half grains. The instrument is
from lamp 10 conferred through . tense on
the mirror and reflected back on TO q
graduated scale. The currents of electri.
city sent through the cable enter the mag.
netic coil, and cause the needle TO be de-
dected from side 70 side, the motions being
made TO form Geographic characters.
These minute vibrations are read of by an
operator, who calls out each word 40 he
receives II TO copyist, usually IN IN ad-
joining lighted room.
The principle OF the mirror is, in the
main, that OF the recorder now used on all
the principal cables, but in place of the
small coil large upright magnet is used,
1uO mOoluC1tiOu OI tue ueeOl6 arrange.
ment is suspended between the two poles,
and has . very delicate glass tube, bent
like . siphon, attached TO it IN place of the
silvered glass. One end of the siphon rests
IN reservoir OF ink, and the other end il
adjusted WITHIN . hairs breadth of the
surface of the white paper riboon winch
is drawn beneath IT. Anime Ink Is forced
through the siphon by IN elsclrlc process.
and - the tube moves to the right anu
left with the currents it traces the
movements on the paper ribbon. As the
ribbon passes before the operator the
marks are read upward and downward:
the upward marks correspond in sense to
the dots and the downward to the dsshes
OF the Morse alphabet. Owing to the
pecuiiarities Of spaced letters" in the
ordinary Morse alphabet which cannot be
transmitted on the recorder. an entirely
different combination OF characters, called
the continental code, il used. Unlike the
Morse, the dots and dasnes of which are
always alike, or should be, unless the
operator is . ham, the cable signals vary
very much IN proportion TO the length of