I am lucky enough to own a heliograph, having recently bought it from
another BSS member. It dates from WW1, and looks just like the one in Peter
Mayer's jpeg with the exception that the sighting vane is more complex, with
a set of cross wires and a fold-down vane on which the dark spot from an
unsilvered spot in the centre of the mirror is aligned.
It's described as a Mk5, and comes with its own mahogony tripod and set of
spares etc. There is a range of attachments (most in very solid brass)
included in the leather carrying bag. One of these is a duplex mirror, used
when the sun and the receiving station are in opposite directions. This
mirror, which fits on the arm were the sighting vane is in the jpeg, is
always used to direct the sun onto the main signalling mirror when the sum
of the angles of incidence and reflection is 90 degrees or more. The main
mirror has a slow motion screw so that the operator can track the sun during
long messages.
I have full instructions on how to set up and use, but they run to several
pages so I won't reproduce them unless anyone contacts me directly.
The accompanying book ("The Heliograph - A short history" by Alan Harfield,
pub Royal Signals Museum, 1981, ISBN 0950121835) describe achieving signal
ranges of up to 53 miles with a 5 inch mirror (like mine), and up to 83
miles to 9" and 12" mirrors. This was done in the mountains in northern
India. Heliographs were also much used in the States, for example by
General Miles in 1878/9, and there are various quotes from Geronimo, who
believed the flashes were spirits!
All I need to do now is find someone else with a heliograph, and then we can
have aconversation (after I've learned Morse!)
Regards,
John Davis
