Heliograph Peak Path #328A
Typically when you are in open country, chances are you’ll catch a flash of daylight on the windshield of a automobile many miles away.
An observer 6 miles. distant would see none of its mild if he were more than 50 yds. on one side of the precise alignment, whereas a flag sign could possibly be read from nearly every hill within vary. None of the physical exertion required for fast signalling with the flag is required to control the instrument at a high price of speed. The entire apparatus is packed in a light and moveable kind. An alternate method of using the heliograph is to maintain the rays permanently on the distant level, a shutter of some form being utilized in entrance of it to supply obscurations.
During the First World Battle wired telephones were used where possible however this involved laying landlines which was a hazardous job … Read the rest