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Dead medium: Mirror Telegraphy: The Heliograph, the Helioscope, the Heliostat, the Heliotrope
From: boneill@allinux1.alliance.net (Bradley O'Neill)
Source(s): 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.