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Subject: Dead Media Working Note 02.7
Dead Media: Mirror Telegraphy: The Heliograph, the
Helioscope, the Heliostat, the Heliotrope
From: boneill_AT_allinux1.alliance.net (Bradley O'Neill)
Source:
Plum, William Rattle, 1845-1927.
TITLE The military telegraph during the Civil War in
the United States with an exposition of ancient and modern
means of communication, and of the federal and Confederate
cipher systems; also a running account of the war between
the states. Microform.
PUBLISHER Chicago : Jansen, McClurg & Co.,1882.
PHYSDESC 2 v. : ill., port., maps, facsim.
SERIES 1) Microbook library of American civilization;
LAC 22395.
All (((comments))) by Bradley O'Neill.
pages 29-30
HELIO-TELEGRAPHY: "As of late (((read: late-mid 1800s in
Europe/US))) the rays of the sun are doing courier service
where the electric telegraph could not be built or
operated, and such has been the success of sun
telegraphing, that it constitutes a new and rapidly
developing wonder. This mode of signaling is variously
designated as mirror telegraphing, heliographic,
helioscopic, heliostatic and heliotropic, all of which
seem to be essentially identical in the main principles.
But the instruments by which the rays are concentrated and
reflected differ somewhat, and hence some are better
calculated than others to work at great distances. The
heliostat was invented by Gravesande, about a century and
a half ago.(((circa 1718?)))
...In 1861, officers of the United States Coast Survey, at
work in the Lake Superior regions, demonstrated the
usefulness of the mirror, equatorially mounted, for
telegraphic purposes, and succeeded in conveying their
signals with ease and rapidity a distance of ninety miles.
During the same year, Moses G. Farmer, an American
electrician, a man of infinite invention succeeded in thus
telegraphing along the Massachusetts coast from Hull to
Nantasket. The next year some English officers introduced
the system into the British navy, with modifications and
improvement, using at night an electric or calcium light.
The signals communicated are made by alternately exposing
and cutting off continuous rays of light reflected from
one station to another.
page 30
MANCE HELIOGRAPH, "an instrument used by the English,
telegraphing is done by pressing a finger key, whereby,
flashes of light, of long or short duration, are emitted.
These flashes and intervals or spaces are easily made to
indicate what in the Morse alphabet are shown by dots,
spaces, and dashes... In this way the Morse alphabet may be
telegraphed as easily as by an electrized wire. Indeed,
ungodly parties have before now, at church, telegraphed
across the room without awakening suspicion, by a mere
movement of the eyelids. It is reported that during the
seige of Paris (1870-1), messages were telegraphed
therefrom twenty and thirty miles, by the reflection of
calcium lights... The Mance Heliograph is easily operated
by one man, and as it weighs but about seven pounds, the
operator can readily carry it and the tripod on which it
rests...During the Jowaki Afridi expedition sent out by
the British-Indian government (1877-8), the heliograph was
first fairly tested in war.
page 30
THE HELIOSTAT, "is said to be the first instrument for
mirror telegraphy used in war (((which war is not
explicitly indicated, but likely the US Civil War))). The
mirror receives and reflects the sun's rays, and a
clockwork attachment keeps the mirror position to receive
the direct sunbeams, which in Nevada, U.S., are said to be
so bright as to be hurtful to the eye at a distance of
forty miles. Behind the mirror, in the very center, some
of the quicksilver is removed, leaving a very small,
round, clear space in the glass, through which the
operator looks and may watch the reflection from the next
station.
page 30
THE HELIOTROPE reflects the rays by mirrors but has no
clockwork.
Enjoy,
Bradley.
Dead
Media | 0.01-02.0 | 02.1-04.0
| 04.1-06.0 | 06.1-08.0 |
08.1-10.0 | 10.1-12.0 |