An aerial shot of the Barker Engineering Library reading room from the 1930s.
Now, for the first time in more than 70 years, the space beneath the dome — the Barker Library reading room, a 75-foot rotunda with an intricate 27-foot skylight, or oculus — has been restored to its original splendor. “If the Great Dome is MIT’s signature building,” says Stephanie Hartman, a librarian at Barker who has been researching the history of the reading room, “then in some sense, the reading room is MIT’s signature space.”
The restoration of the reading room was just part of a renovation of the dome itself that involved, among other things, lifting off all of its limestone cladding so that a new waterproof membrane could be injected beneath it.
The dome of the reading-room rotunda, whose diameter and height are both 75 feet, is nested inside the 100-foot-wide Great Dome; the two domes converge at the circular oculus, which is set in the center of both. In 1942, the oculus met the wartime fate of many skylights in U.S. cities: It was covered over, to avoid providing an easily identifiable nighttime target for enemy bombers.