Since the ancient times, man has attempted to unravel the mysteries of the deep-sea. Today such sophisticated underwater breathing devices have been produced which enable man to stay underwater for long periods. The first man who invented the first practical diving apparatus was a German Scientist named Augustus Siebe. The apparatus contained a metal, diving helmet with a shoulder plate attached to a waterproof leather jacket. A tube running from the helmet was attached to an air pump. This was the first of many major experiments he carried out in trying to perfect a safe method of staying and working underwater. In 1830, he created a complete suit and helmet with air valves. Although many improvements have been made, Siebe's principle remains in universal use.
Seven essential things that a deep-sea divers should follow:
An air pump for pushing air downwards to him.
A helmet usually of steel, with glass windows to see.
A flexible waterproof suit fitting closely at wrists and ankles.
A length of air tubing that must be flexible but must not collapse under the pressure of water.
A pair of boots to keep feet on the bottom.
Lead weights, which are hooked to chest and back, to prevent floating up to surface.
A lifeline to communicate with the surface by a system of jerks.
A telephone, which the diver can speak to the surface, is fitted to most of the diving apparatuses.
How to manage the water-pressure and diving suits.
Water pressure is a big problem to the deep-sea divers. The further a diver goes, more becomes the pressure of water around him. Therefore, the air pumped down must enable him to breathe properly and balance the water pressure outside. Divers working at great depths do not use the ordinary flexible suits. Instead, they use metal suits. Such suits are lowered and raised by cables.
Earlier the divers used to breathe ordinary air, which contained nitrogen. This was dangerous. Deep down the sea pressure is very great. This causes the nitrogen to dissolve in the blood. When the divers surfaced, the pressure quickly returned to normal. This caused nitrogen to bubble out of the blood. This can be very painful and even kill the diver. This condition is called bends or caisson disease. In order to get rid from it, today divers breathe a mixture of gases -oxygen and helium. Helium does not dissolve in the blood so it is much safer to use. Breathing helium makes divers speak with a high, squeaky voice because sound travels three times as fast as it does in air.
Divers perform many important jobs. They are needed for the construction and repair of bridges. They study plant and animal life beneath the surface of water. They aid in finding drowned people. Diving is also a sport today.