Bathyspheres are special chambers designed for use in deep-sea exploration. A traditional bathysphere has the general rounded appearance of a sphere, and is equipped with pressure-resistant windows, allowing the occupants to observe the terrain and marine life surrounding the chamber. First envisioned in 1928, the device made it possible for humans to explore underwater areas that previously were beyond the technology of the day.
A bathysphere is lowered into a body of water using strong cables that are operated from a ship. Cranes help to control the rate of descent as well as the depth that the chamber reaches. The door into the device is designed to be watertight, making it easier to pressurize the cabin and keep the pressure at a level acceptable for humans. Spotlights make it possible to illuminate the area immediately around the device, catching glimpses of different types of marine life. The earliest designs included a series of high-pressure cylindrical tanks that contained enough oxygen to allow the divers time to make a relatively thorough survey of the general conditions in the immediate area.
John H.J. Butler is credited with designing the first bathysphere in 1929, working off a general concept that was conceived by Otis Barton the year before. The first design was extremely heavy and proved unworkable. A second attempt yielded a design that offered all the safety features found in the initial design, but was light enough for transport and use with the steel cables of the day.
Barton turned to William Beebe, a noted naturalist and explorer, to find financial backing for the construction of the new bathysphere. On 6 June 1930, the pair executed the first manned dive with the new device, reaching a depth of 803 feet, or 245 meters. Within four years, the pair had set a new record, managing a successful descent of 3.028 feet, or 923 meters. That record stood until 1949.
While the bathysphere made it possible to explore ocean depths that had previously been impossible for humans to manage, the device did have limits. The cables used to lower and raise the device would only remain workable up to certain depths. In addition, the device had no means of independent locomotion, making it necessary to lift the bathysphere back to the ship, move to another location, then lower the device a second time. In time, a similar device known as a bathyscaph, was developed; this device was capable of a limited degree of self-locomotion and could manage depths that were beyond the capabilities of the bathysphere.
Today, the first working bathysphere is on display in the United States. Housed at the New York Aquarium in Coney Island, visitors are treated to presentations on the history of the device, as well as archived footage that chronicles the early expeditions involving Barton and Beebe. While deep-sea exploration has advanced far beyond the capabilities of that first bathysphere, much of the knowledge acquired during its construction and later use helped to make modern methods of exploration possible.