Cartographic Miscellany

THE FISK SOLARISCOPE
"An essential aid to all users of Short Wave Communications"
Designed by Sir Ernest Fisk (1886-1965)
Produced by E.M.I. Sales & Service Limited., Hayes, Middlesex. 
No date but produced shortly after the second World War c.1950.

Double Mercator projection map printed on cardboard tube. Bakelite caps top and bottom, top cap removeable. Overall size 12cm high x 8.5cm dia. 4 celluloid plastic sleeves printed with night shadows for each month of the year stored within the tube. Each sleeve fits to outside of the cylinder and is rotated for time to indicate the area of the world in daylight and darkness at any time of the year. Its primary purpose was an aid for short wave radio communication which were affected by solar conditions and required frequency adjustments accordingly. Also stored within the tube is a 20 page booklet explaining its use, a gazetteer of the principal short wave stations across the world transmitting before the war and which "Doubtless...will be back on the air again soon.", and tables of waveband allocations.
Missing label to top cap, chips to bakelite caps including a glued repair to small piece of the removeable top cap.
A rare item, complete with all celluloid sleeves and original booklet.