Editing Timeline of diving technology (section)

===The demand regulator reappears===
* 1934: [[René Commeinhes]], from [[Alsace]], invented a breathing set working with a demand valve and designed to allow [[firefighter]]s to breathe safely in smoke-filled environments.{{citation needed|date=February 2017}}
* 1937: [[Georges Commeinhes]], son of René, adapted his father's invention to diving and developed a two-cylinder open-circuit apparatus with [[diving regulator|demand regulator]]. The regulator was a big rectangular box between the cylinders. Some were made, but [[World War II|WWII]] interrupted development.{{citation needed|date=February 2017}}