Some inventions are said to be ahead of their time, and some behind their time; but most inventions arise as a result of present needs, or as a result of a new development that enables an existing idea to be produced.

Think of the example of space travel.  Space travel wasn’t possible in the 1930s because the rocketry technology wasn’t available — that was only developed during the Second World War. So it was with the diving helmet; everybody knew what they wanted to do, but they couldn’t make it work until the materials and technology became available.

Key words: Diving, diving helmet, Deane helmet, James helmet, Halley helmet, diving hoses, diving pumps, Diving Museum, Gosport, England.