What's the difference between i.e. and e.g.?
A hollow, spherical steel diving chamber in which people are lowered by cable from a surface vessel to explore the ocean depths. In 1934 a bathysphere carrying William Beebe and an associate reached a record depth of over 923 m (3,028 ft). Because space in the bathysphere is cramped, dives longer than three-and-a-half hours are intolerable, and it was eventually supplanted by the bathyscaphe.
spherical steel vessel for use in undersea observation, provided with portholes and suspended by a cable from a boat. Built by the American zoologist William Beebe and the American engineer Otis Barton, the bathysphere made its first dives in 1930. On June 11, 1930, it reached a depth of 400 m, or about 1,300 feet, and in 1934, Beebe and Barton reached 900 m, or about 3,000 feet. Through these dives, the bathysphere proved its qualities but also revealed weaknesses. It was difficult to operate and involved considerable potential risks. A break in the suspension cable would have meant certain death for the observers; surface waves and resulting movement of the boat could have produced such a fatal strain. Because of these disadvantages, the bathysphere was supplanted by the safer, more maneuverable mesoscaphe and bathyscaphe.