Living Underwater.

There were Sealab projects in the 1960s numbered I, II, and III. The Sealabs were submarines of sorts equipped for scientific study. Some scientists thought that people could live and work underwater for long periods, and the Sealab project was an attempt to find out what problems such conditions would pose. The Sealabs were underwater experimental chambers where people would stay submerged for days at a time to work in and study the oceans. Sealab I submerged off Bermuda in 1964, and four people stayed down for nine days at 192 feet. This was a warm ocean area. The next step was Sealab II, taken to a cold ocean region.

Sealab II.

Sealab II cost $850,000, a phenomenal price in its day. It was a 12-by-57-foot cylinder made of steel and containing life-support equipment and scientific research instruments. The "submarine" was attached...