Hollow Square, Jack Tefft, 1970

Note: This reel-to-reel tape was labeled "Hollow Square, Jack Tefft." Upon digitization, it was found that the tape actually contains two audio recordings: 1) Hollow Square talk: Fire and Brimstone! (Volcanoes and the Sulfur Cycle), Richard D. Cadle, September 18, 1970; 2) Hollow Square talk: GHOSTS Riding the Skies Over Ascension Island, Henry van de Boogaard and Jack Tefft, December 11, 1970. Digitized versions of the recordings are available in the OpenSky digital repository.