• History of aqualung

    "Ichthyander went deeper and deeper into the twilight depths of the ocean. .." Who does not know the hero of the novel by Alexander Belyaev, The Amphibian Man? Who did not dream, like Ichthyander, to travel to the little-known expanses of the underwater world? This man's dream is many thousands of years old.

    In ancient Greece, divers fishing for fish, purple shells, oysters, sponges, copper ore, used leather pipes that emerged on the surface of the water, and metal boilers protecting the head. This equipment can be considered a prototype of modern scuba gear. Ancient divers engaged not only in peaceful work. They played a big role in the wars of that time.

    Underwater bell. XVIII century.

    In one of the ancient Greek legends it is said that Skill and his daughter Hydna contributed a lot to the defeat of the Persian fleet, which in 480 BC came to the shores of Greece. Brave divers managed to cut the anchor ropes of enemy ships shortly before the storm, which dispersed and damaged ships. The Persian fleet suffered enormous damage.

    Divers-warriors strengthened anchors, changed worn ropes, repaired underwater parts of ships, served as scouts, signalmen, sappers. In the fleet of Ancient Rome, even a special body of divers operated.

    Submarine. XVIII century.

    Information about the ancient tribes - ichthyophages, skilful swimmers and divers, who once lived along the shores of the Persian Gulf, the Red Sea and in West Africa, were also preserved. They swam swiftly and magnificently, like fish.

    Ancient Greek writer Plutarch in the composition about Antony and Cleopatra describes such an episode. Anthony, wishing to surprise Cleopatra with his skill in fishing, instructed one of the divers to put the fish on the hook under the water. Fish from the king caught one after another. But the triumph of Antony did not last long. Clever Cleopatra quickly guessed what was wrong, and also called for the help of a diver who outstripped the diver Antonia and planted a salt fish on the hook.

    Diver. XVIII century.

    There were divers in Russia. They were distinguished by strong health, endurance and mighty power. They were called diving people and used in the fishing industry of the Volga and other fish-rich rivers, as well as for pearls on the rivers of the North.

    In the Middle Ages, the art of divers was forgotten. But long hollow reeds were used by our ancestors, crossing rivers or escaping from enemies. In the ancient chronicles of Pskov it is written that with the help of such a trick many citizens evaded military service, hiding at the bottom of lakes and wells.

    In the Renaissance, people began to think again about the problem of swimming under water. Humanity owes much to the genius of Leonardo da Vinci - an artist, a scientist, an engineer. Much of what he came up with is used by scuba divers even today. He invented a glove with spread fingers and membranes, reminiscent of a duck paw, a device for underwater breathing by means of a reed tube and an underwater telephone; he advised divers how, for example: "Carry a sharp knife with you, so as not to get caught up in any network."

    All devices created by designers( whether they are aqualungs or spacesuits) are based on the fact that a person takes with him a stock of the respiratory mixture or receives it from the surface. True, the water itself contains dissolved oxygen - about 10 grams per 1 cubic meter, and a person needs at least 30 grams of breath for 1 hour. But how to extract oxygen from water? Fish with the help of gills successfully cope with this task. Dissolved in water, oxygen passes through the thinnest membranes in the gills into the circulatory system, and the excess carbon dioxide present in the blood seeps through these same membranes into the water. Can not you use this hint of nature?

    For quite a long time, experiments have been conducted with a thin film of silicone rubber, a few microns thick, which acts as an artificial lung tissue: without letting water pass, at the same time it allows oxygen dissolved in water to penetrate into the enclosed space. If such experiments succeed, oxygen can be extracted from the environment surrounding the aquanaut and anyone can become Ichthyander.

    Do you know?

    How does water density change with depth? Is A.Belyaev right, who wrote in the novel "Amphibian Man": "He sank more and more slowly. The water became denser, it already pressed on him, it became more difficult to breathe "?

    The density of most liquids is almost the same at any depth - the fluids are practically incompressible. So the science fiction writer has somewhat exaggerated the effect of changing the density of water. And to breathe at a depth becomes more difficult because of the increase in the water pressure.