Valley of the Dragons (1961 film) to try and get on the earth the next time the comet approaches. The film was produced by Al Zimbalist who says he was given a copy of the Verne novel that his 16 year old son Don had found in a London bookshop. Director Edward Bernds says the novel had not been published in the US due to its anti semitism. Jules Verne adaptations were in vogue at the time ever since the success of "Twenty Thousand Leagues Under the Sea" and "Around the World in 80 Days". Zimbalist had the rights to footage for "One Million B.C." (1940).
Twenty Thousand Leagues Under the Sea of underwater breathing apparatus designed by Benoit Rouquayrol and Auguste Denayrouze in 1865. They designed a diving set with a backpack spherical air tank that supplied air through the first known demand regulator. The diver still walked on the seabed and did not swim. This set was called an "aérophore" (Greek for "air-carrier"). Air pressure tanks made with the technology of the time could only hold 30 atmospheres, and the diver had to be surface supplied; the tank was for bailout. The durations of 6 to 8 hours on a tankful without external supply recorded for the Rouquayrol set in