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.
The same design is seen on 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 undersea photography for Stuart Paton's 1916 silent movie production of Jules Verne's novel Twenty Thousand Leagues Under the Sea was done from this chamber. This was the first movie to feature underwater filming.
This 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.
First day of Use of “SEA FLOOR” Post Office Cancellation
Cover Autographed by Photographer Captain J(ohn) E(rnest) Williamson
Addressed to Wollaston, Massachusetts with August 21, 1939 Receiver Postmark
Franked with Four Pence “Sea Gardens, Nassau” Definitive of July 1, 1938
“SEA FLOOR” Post Office Cancellation for the Centenary of the Penny Black May 6, 1940
Enlargement of Cachet Depicting the Sea Floor Post Office
In the years since its closure, the Williamson's Photosphere has been commemorated on at least two stamp issues. It was depicted along with the bathyscape Trieste on the 25 centime denomination of Monaco's issue for the "Man Under Water" exhbit at the Oceanographic Museum issued on December 12, 1962. On August 16, 2014 the Bahamas issued a set of four stamps commemorating "The 75th Anniversary of the World’s First Undersea Post Office." The designs featured "The 1914 Williamson Photosphere Film Project" on the fifteen cent denomination, "Underwater Photography" on the fifty cent denomination, "The Williamson Photosphere" on the sixty-five cent denomination and "John Ernest Williamson 1881-1966" on the seventy cent denomination.
J.E. Williamson's Photosphere as depicted on a stamp from Monaco issued in 1962
Stamps Issued by the Bahamas on August 16, 2014 to Commemorate
the 75th Anniversary of the First Undersea Post Office