The Maryville times. (Maryville, Tenn.) 1884-1944, 1886-08-09
THE ART OF HELlOGRAPhY.
Description of the Heiios:at-How 1t Is
Worked-Limited Usefulness.
FIRED A. Hunt in Chicago News.

Description of the Hoiios:at-How 1t Is
Worked-Limited Usefulness.
FIRED A. Hunt in Chicago News
The heliostat-the proper name--is
used with success in the Soudan, and
has been used with much success in
America, as in Montana, before the in
PRODUCTION of the telegraph along the
Yellowstone valley, there We're series
of hello tat stations between Forts
Keogh AMI Custer. But the heliostat is
a troublesome instrument at tile est,
for tho san is not at all times available.
In the ,oudan, where the country has q
vast extent Of plane surface, EglIo5tGt
stations can easily he erected, and the
sun being Il pretty constant factor, mes
sagCs ac ras!y transmitted, ut in a
broken or t inferred country, where the
sun Lctoues clouded, the heiiostat is
not so reliable or useful, and one tele-
graph is worth dozen hcllostats.
The h! oSlat consist of a circular
mirror at'g iucnes in diameter, mounted
On irloN. provided with suitable adj
lustmtnt., 80 that the suns light can
be rec we'd upon it and reflected at a
distant station" So far, correct; but
it additionally has small rod attached
to the top of the mirror rests, which
has a small amount of perpendicular
play-the vertical oscillation deter
minable by set-screws. To operate it
the telegrapher sei2es a little button on
this rod and ''iiggles' the mirror up
and down; q long liggle makes the tele-
graphic long dash, medium .iggle
the telegraphic dash, and a short iiggle
the Geographic dot, and combinations of
these three signs, according to the
torse code. form tie means of sending
messages The receiver simply watches
the flashes of sunlight, and the duration
and the intervals between the flash are
read by him as readily as though he
were receiving from telegraphic
"sounder." One is optical telegraphy
and the other aural, that is all the
difference.
To learn the art Of photography the
sender takes the button, just as a tele-
graph operator does his key, and ap.
plies his eye to the center of his little
mirror. In the center is spot without
any mercury, and through which the
operator can see. In front of the hello
stat, and distant about two yards, i.
placed an upright wand with four dis
tinct marks on it, making divisions or
its verticality, the lower one being hal
the length or height Of the next, ant
the last division being twice the length
of the first; something like a yard-sticl
with One-quarter, one half, and yar(
notches on it. The operator defects
the mirror, and a sunbeam glances W
the stick; according to the depth Of tn,
"jiggle" or detection the sunbeam
dances higher or less high, and then tn
operator understands that the sun
beams jump from the first notch up
ward to the second is a telegraph dot
from the lowest notch to the third motel
is dash, and from the lowest notch tt
the upper is long dash; the vertica
length of the depression of the buttol
answering to the period that a tele
graphic key is kept down and the cir
cult is left open.
| | have seen messages read just a
ICduliJ UudG WCIC SeuC lIOH SthGlOt
thirty miles away, as though received
from a sounder at ones ear, but til,
proclivity of the sun to get behind ,
cloud or retire from heliostatc servic,
at importune moments seriously mar
the efficacy of this beautiful and scien
titic little instrument. They are readily
transported and easily adjusted. Blu
for field service in any country or il
any condition of atmospheric change
the torch signals by night, and the fla,
signals by day, of the United State
signal service, are certainly the mos
efficient and reliable, while for long dis
tances between stations, fire flashes a
night and smoke-with interrupte,
smokiness-for day are the best. In
dams have longed used mirrors as tn
means of conveying intelligence, an
the idea is utilized in cable message
in precisely the same form as in tn
heliostat. Indians also use smoke TO
signals, making clashes" by GOVERN,
the smudge with a wet blanket and then
by removing it, allow another gust q
smoke to arise in the air. Possibly thi
may be the origin of the proverb abou
throwing wet blanket on the mat
ter"