On Wed, 23 Jun 1999, Tony Moss wrote: > In my impecunious searches of WWII 'surplus' stores back in the 1950s I came > across a "Portable Heliograph Set' in a pouch. It was simply a mirror about > four inches across with a sighting hole in the middle. A length of cord > attached it to a short rod with a bead on top. > > In use the mirror was held in one hand near to the operator's eye. The cord > was then stretched tight and the 'bead' used to 'sight' the target. If the > mirror was then rotated until a sunray coincided with the bead above the > other outstretched hand a flash of sunlight would be directed at the target. > > It all seems rather 'iffy' but I suppose was intended as an emergency device. > > Has anyone any experience of it?
Good grief, Tony, that brings back memories. I tried one of those mirrors once, and it worked quite well. Unfortunately, I didn't think to have a confederate stationed at the 'target' and so no message was sent nor received. They were for emergency use, but could be surprisingly effective. An intriguing thread, indeed! John
