Peter Mayer contributed > > My recollection is that they were >used by military forces in the 19th century in places like India. (I have >a half-baked recollection that Kipling refers to one in a poem...¿Is that a >source?!) > 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? ....and then there was the mechanically luscious Mk.14 bombsight made by 'The AC Sparkplug Company'.....still have it....too beautiful to cannibalise....Now there's a sundialling challenge! Tony Moss