The Manitowoc tribune. [volume] (Manitowoc, Wis.) 1866-1878, 1869-06-24
TELEGRApHY.

Teleg-aphy may, with propriety, be
considered one of the branches of engi-
neering, and is peculiarly of modern de-
velopment. A clever writer says that it
mag be read by each of the five senses.
On land lines each signal is made by sus-
pending the flow of the electric current,
for two different intervals Of time, called
dots and dashes' the use Of which, in
different orders, constitutes the alphabet
OF the telegraph. When they are print
ed they are read by sight but ordi-
narily the operator reads them by
sound as easily as the musician reads
the letters Of the scale by the same sense.
If the operator has no instrument, he
will grasp the wire in his hands, and
read the signals by feeling the inter-
missions of the flow of the electric cur
rent. In like manner, by placing the
wire across his tongue he can taste the
same intermisson (but this is danger
Gus experiment. And it is said that
the electricity can be made TO dissolve a
chemical and produce pungent odor in
the Geographic alphabet, which can be
read by smelling but for this Go not
vouch. | believe that the method Of
signalling through the Atlantic cable is
known In detail to but few persons. The
operation is exactly reverse from that on
the land lines. The gutta percha cover
ing OF the copper wires, under the pres
sure of the great depth ofwater, becomes
an absorbent of the electricity which Is
being sent through them to the extent of
go per cent. The first portion of the
electric wave Of 10 per cent crosses the
ocean Il 700 miles, In two seconds, and
it would be followed by succession of
waves from the restoration of that por-
tlon OF the electricity which has been
absorbed by the gutta percha in lmpul
ses, and the signal would be repeated like
echoes, and produce not only confusion,
but great delay. To remedy this Proees-
sor Marley introduced a key, which sends
alternative currents positive and negative
at such intervals as allow the first wave
of ten per cent. to pass forward, and then
that portion absorbed by the covering is
neutrallzed by Its opposite, and the cable
is cleared for the transmission If second
pair of currents The battery used is
very small one three of Daniels cups
and the signal being only ten per cent. Ct
this small current, is pc,ferless to move
any of the other instruments In use on
land The instrument used consists of
minute polarized needle, suspended on
single strand Of SPIDERS web, or one
from the silk worm. In the middle Of
this minute needle is placed an almost
microscopic mirror, which reflects a sin
gle ray of light from powerful lamp. :
The currents of electricity effect this
needle alternately to the right and LETT
for space of time corresponding to that
occupied in the signal on the land line,
the same kind of alphabet being used in
both cases. The receiver mot operator}
sits in dark room. and the small mirror
reflects the ray Of light upon piece of
paper before him, on which IA black line
is drawn, to the right and left Of which
the light is alternately reflected The
receiver reads these signals by sight,
and transmits to another person, out
side of the dark room, by means of an
ordinary instrument. 4 short time ago,
Gen. Reynolds told me that he had sent
a message, without either wire Or cable,
ninety two miles, across an arm of Lake
Superior, by means of the Heliotrope or
mlrl or, and on the return of his messen-
ger (who had been sent with a written
copy he found that the Heliotrope mes
sage had been received, understood and
obeyed. He had two assistants who bad
been Geographic operators. who had for
whole summer been amusing themselves
in talking to each other with these in
struments, though they were stationed
ten, twenty or thirty miles apart When
the rebel General Morgan made his great
raid through Indiana and Ohio, he cap
tured one OF my operators, and COMPEL
ed him to telegraph, in General Lew
ifillace's name, to Cincinnati, asking
how many regular troops there were in
that city. Morgan read by sound, and
therefore the operator did not dare to
intimate that he was under duress, and
could only venture to add an extra in
itial to his own signature. The receiving
operator at Cincinnati knew that Morgan
was in that neighborhood, and suspect
ing, from the extra initial letter, that ali
was not right, replied, exaggerating the
force of the regulars; aud the conse-
quence was. that Morgan CHI anged his
route to circuit of twenty miles beyond
the city, and thus saved it from sack,
and the probable loss of millions Of dol
lars.