Undersea Post Office Issue
This stamp depicting an undersea post office was issued on January 7, 1965. The same design is
seen on the overprinted issue of May 25, 1966 and the decimal definitive issue of May 25, 1967.
In 1914, marine engineer Charles Williamson filmed sea life in the waters off the
Bahamas. A chamber on the sea bed was connected by a steel tube to a support vessel
called Jules Verne III. The Photosphere project was overshadowed by the outbreak of World War I.
The marine engineer's son, Captain J.E. Williamson, undertook a research project and on August 16, 1939 opened an underwater post office from which covers
were dispatched to dignitaries such as King George VI and President Roosevelt. From 1939-1942 covers from this post office were postmarked "SEA FLOOR". Underwater scenes for E.H. Griffith's 1941 technicolour film, Bahamas Passage, were filmed from the Photosphere. In the late 1940's the chamber was removed from the water.
This King George VI pictorial definitive from the issue of 1938 was in use when the "SEA FLOOR"
post office was open. It depicts the marine life that could be filmed from the Photosphere.