Bathyscaphe

Bathyscaphe, submarine vessel designed to operate at great depths. The first such vessel was invented in 1947 by the Swiss physicist Auguste Piccard, and explored the ocean bottom. In 1954 it reached a depth of 4,000 m (13,125 ft) and operated under water pressures up to 0.42 tonne/sq cm (about 400 times atmospheric pressure). The bathyscaphe Trieste, built in 1953, set a world record on January 23, 1960, when it descended 10,912 m (35,800 ft) to the bottom of the Mariana Trench, deepest known point in the oceans, 402 km (250 mi) south-west of Guam. It withstood a pressure of 1.17 tonnes/sq cm (1,000 times atmospheric pressure) at that depth. The craft, which carried petrol for buoyancy and iron pellets for ballast, descended when water was pumped into air tanks at each end and ascended when water was pumped out and the pellets released. The dive, manned by Jacques Piccard, the son of Auguste Piccard, and by Lieutenant Donald Walsh of the United States Navy, yielded important geophysical information. See Deep-Sea Exploration; Geophysics.