Associate Professor of Geology Karen Lukas and Associate Professor of Anthropology L. Lewis Johnson gave a Sigma XI lecture on “Natural History and Cultural History: Galapagos Islands and Machu Picchu” in Sanders Physics.  Sigma Xi, an honorary scientific fraternity open to faculty members with associate membership for outstanding students, had 500 chapters nationally.   Vassar established Sigma Xi at the club level in 1959 and an active chapter of Sigma Xi in 1995.