Tony Moss <[EMAIL PROTECTED]>
> 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 f our inches across with a sighting hole in
> the middle. A length of cord attache d 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 w as then stretched tight and the 'bead' used to
> 'sight' the target. If the mirr or was then rotated until a sunray
> coincided with the bead above the other outs tretched 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?
[...]
> Tony Moss
When I was growing up my brother had a "sun signaling mirror." I
think he got it through boy scouts, though when I joined scouting
later I never came across one. I remember that the instructions were
printed on the back of the mirror. My understanding of it was that it
was for emergency use, allowing one to indicate his position to
another who is some distance away. In my mind I pictured the scenario
of one lost in the woods seeing a search party (or search plane) and
wanting to flash a light in that direction to indicate his presence.
As I recall, the mirror was rectangular, about 4 x 6 inches; in the
center it was double thick (a round 1-1/2 inch annular attachment
giving the extra thickness), with a 1/2 inch clear hole in the center.
What amazed me was that the user looked through the hole and saw an
orange-yellow spot that indicated where the flash was going. I always
wondered how that worked (and to this day do not understand it). If
anyone can explain that to me I'd be much obliged.
Jim
------------------- ---------------------- --------------------
| Jim Cobb | 540 Arapeen Dr. #100 | [EMAIL PROTECTED] |
| Parametric | Salt Lake City, UT | (801)-588-4632 |
| Technology Corp. | 84108-1202 | Fax (801)-588-4650 |
------------------- ---------------------- --------------------
But there's no need for turning back
'Cause all roads lead to where I stand.
And I believe I walked them all
No matter what I may have planned.
-- Don McLean, Crossroads
