bathysphere

thumb|right|200px|The Bathysphere on display at the National Geographic museum in 2009 The Bathysphere () was a unique spherical deep-sea submersible which was unpowered and lowered into the ocean on a cable, and was used to conduct a series of dives off the coast of Bermuda from 1930 to 1934. The Bathysphere was designed in 1928 and 1929 by the American engineer Otis Barton, to be used by the naturalist William Beebe for studying undersea wildlife. Beebe and Barton conducted dives in the Bathysphere together, marking the first time that a marine biologist observed deep-sea animals in their native environment. Their dives set several consecutive world records for the deepest dive ever performed by a human. The record set by the deepest of these, to a depth of on August 15, 1934, lasted until it was broken by Barton in 1949 in a vessel called Benthoscope.

==Origin and design== thumb|left|200px|The instruments aboard the Bathysphere In 1928, the American naturalist William Beebe was given permission by the British government to establish a research station on Nonsuch Island, Bermuda. Using this station, Beebe planned to conduct an in-depth study of the animals inhabiting an area of ocean, from a depth of to the surface. Although his initial plan called for him to conduct this study by means of helmet diving and dredging, Beebe soon realized that these methods were inadequate for gaining a detailed understanding of deep-sea animals, and began making plans to invent a way to observe them in their native habitat.