"Man carries the weight of gravity on his shoulders. But he has only to sink below the surface to be free"
Jacques Cousteau
The aqualung, invented in 1943 by Frenchmen Jacques Cousteau (1910-1997) and Emile Gagnan (1900-1979) transformed underwater exploration, engineering, and marine biology. For the first time, divers could .move.-around freely, and undertake lengthy dives. The invention consisted of compressed air in cylinders, worn on the diver's back and connected to a mouthpiece through a regulated "demand" valve. This Self-Contained Underwater Breathing Apparatus—SCUBA—is very similar to the diving equipment we use today.
Before this aqualung was invented, divers used various techniques for underwater exploration. Snorkeling, using a short tube connected to the mouth with one end above the surface, allows exploration in shallow waters. Attempts to explore deeper using a longer snorkel tube were limited by the diver's need to stay fairly close to the air source. A rebreather system, in which the diver's exhaled gases were filtered, was unreliable and often caused deaths.
Gagnan was an engineer with expertise in gas valves, while Cousteau, a commander in the French Navy during World War II, realized the potential value of free-moving "frogmen" who could attach explosives to enemy ships. Even with their new scuba equipment, there was a lot to learn. Cousteau's first dive was nearly disastrous, as he did not know that oxygen becomes toxic at depths below 30 feet (9 m). After the war, Cousteau continued to lead the development of underwater exploration and became known for underwater filming and photography.
