Irving Friedman (left) and William D. Long in 1958 in a USGS laboratory in Washington, D.C.

Irving Friedman (left) and William D. Long in 1958 carrying out experiments with welded volcanic tuffs at a USGS laboratory in Washington, D.C. Results from these experiments were presented in a journal publication on the hydration of natural glass and formation of perlite (a volcanic glass with a concentric structure). Photo by E. F. Patterson (https://library.usgs.gov/photo/index.html#/item/51dda09ee4b0f72b4471ddad).