Development of Modern Scuba Gear
Humans have long dreamed of moving about freely underwater. There are stories of ancient people escaping from enemies by hiding underwater and breathing through hollow reeds. Diving for sponges and various edibles goes back thousands of years. Humans have long been sailing the oceans for trade. Inevitably, some ships sank with valuable cargo onboard. This necessitated salvage operations.
The first approach to working underwater was simply to hold your breath. This obviously limited the depth at which divers could operate and the length that they could stay down. While some whales can stay submerged for two hours and reach depths of over a mile, most human divers can only hold their breath for about two minutes. To extend the time divers could spend underwater, diving bells were used. These chambers contained a large bubble of air, and were open at the bottom. Using these, divers could simply return to the chamber to breathe, and did not have to return to the surface.
In the twentieth century Scuba (Self Contained Underwater Breathing Apparatus) gear was developed that allow divers to freely move around for extended lengths of time. The Aqua-Lung was invented by Jacques Cousteau and Emile Gagnan in 1943. Cousteau was a naval lieutenant at the time and Gagnan was an engineer. After the conclusion of World War II, the Aqua-Lung became the first successfully mass produced scuba gear. Cousteau went on to use it while making the underwater films which made him famous.