A bathyscaph has a steel-walled observation sphere with a port-hole of great strength to stand the pressures in the deep oceans. The observation sphere is attached to a float which is filled with petrel. As the petrol is lighter than the water, it provides buoyancy. The float also helps to keep the craft the right way up. Heavy ballast in the form of several tons of iron shot or pellets is used to take the craft down. When the vessel needs to come to the surface again, the ballast is released and the vessel floats up, helped by its petrol 'balloon'.
The bathyscaph was invented by a Swiss scientist, Auguste Piccard. He tested it first off the coast of West Africa at Dakar, in 1948. It worked successfully, though unmanned, and went down to 4,500 feet. Another version was built and called Trieste. Piccard went down over two miles in the Mediterranean with this vessel.
Then the United States Navy bought Trieste for research and a number of descents were made by Dr Jacques Piccard, the inventor's son. On January 23, 1960, Jacques Piccard and Lt Donald Walsh of the US Navy descended into the Marianas Trench in the Pacific. They established a world record for deep sea descent which still stands. They touched bottom a 35,802 feet. This was more than 2,000 feet deeper than the ocean bed was thought to be. The pressure of the water was 1100 times greater than the atmosphere. Even at that pressure and depth there were living things, including fish The descent took over five hours and the return trip more than three hours.
Bathyspheres
A bathysphere is a thick-walled sphere with port-holes and equipped for observing marine life. Unlike the bathyscaph it is lowered inti the ocean at the end of a cable which also has ; telephone link with the surface vessel. The observers in the bathysphere can keep in touch and dictate descriptions of what they see. On these deep sea explorations oxygen is carried aboard and chemicals to absorb the carbon dioxide breathed out. The United States ha been prominent in developing bathyspheres Dr C. William Beebe and Dr Otis Barton carried out a series of dives in one off the coast of Bermuda in the early 30s. In August, 1934, they reached 3,028 feet. In 1949, off Santa Cruz California, Dr Barton made a deeper descend with a modified form of bathysphere which he called a benthoscope, meaning 'deep-sea viewer'. He went down to 4,500 feet.
