The Valley Virginian. [volume] (Staunton, Va.) 1865-1895, 1879-05-15
Science and War-signallzing by Sun
shine.

The use of the heliostat in the field adds
| made by our soldiers and sailors. Signals
| by sunshine may be no novelty, but the
present Afghan campaign and the Zulu war
will henceforth be cited as the first in which
the heliostat was employed as an imple-
ment OF warfare. There can be little ques-
ton as to its value to the soldier, for 1t af-
fords at once ready and far-reaching mode
of signalling; but sunshine is an obvious
/ sine qua non to its use. In this country,
| where the Astronomer-Royal tells us the
number of hours of sunshine in the week
sometimes does not go beyond the units, the
helcstat would furnish but an irregular
means Of telegraphing, and Interruptions in
the service would oe both frequent and pro-
longed. But in India, on the other hand,
at special SEASONS. at any rate. sunshine is
the rule rather than the exception, and con-
sequehtly the heliostat furnishes an excel :
lent means of co,LmuI ication which our
scientific soldiers have done well to make use
of.
Heliostat stations are established at this
; moment throughout tile Khyber Pass. and
Gen. Sir Sam. Browne, at Jellala bad has his
| orders passed up to him by dashes Of light
from Peshawur and Ali Musjid. Lord
Chelmsford has of late also been furnished
with heliostats, in order to provide him with
better means of communication along the
Tusela. The plan of working is very sim
Pile. The mirror of the heliostat is placed
50 as to reflect the SUMS image to distant
station and when the Instrument has once
been set the clockwork arrangement, it need
not be said, suff1ces to maintain the mirror
in Is proper position. In this way the dis,
| tant station in question always sees the daz-
zling ray ref cited from the mirror, except
when the latter is purposely obscured. The
appear ance and disappearance Of the bright
>pot Or fl sh constitute the signals. There
is no need for any superntencence when
once the apparatus has been put in working
order. and trained signalmau suffices for
the duty. The ordinary Morse alphabet sup
plies an Ineligible code. ard no one out of
the line of signals can read or understand
the message. As substitute for the dot
and dash, winch 90 to make up the ordinary
written Morse code, the light is shown for
short and long intervals; thus the light
shown for short period followed by a Ion.
period signifies A, while B is represented by
long period followed by three short ones;
in the case Of g, long, short, long, short
signals are made in turn, and to form e, the
letter most frequently used, the light is per-
mitted to shine for one single short period
only.
The intensity of these sunshine signals
can scarcely be imagined by any one who
has not seen the heliostat in working order.
and the distance to which they might BIZ
made to travel, could suitable stations be
provided, is practically unlimited. But
everybody has noticed at one time or anoth-
er, just before sunset, the light striking viv
idly against the windows of house. In
this case the burning spot may be seen for
miles away, and forms the most striking OBJ
ject in the whole landscape. The helostat
signal is obviously brighter still than this,
and the appearance and on-appearance OF
the light is to be appreciated at ten or TWEEN
ty miles distant without the aid Of telescope
or Observation-Disclosures,