Dr. Hoerlin was one of the leading European climbers during the late 1920s and 1930s. With Erwin Schneider, he made many notable first winter ascents in the Alps, for example that of the Peuterey Ridge of Mount Blanc. In those days even a straightforward ascent, as of Monte Rosa, might require starting with skis from near Visp, a fitting task for hard men with little vacation time. In 1930 Hoerlin was chief photographer for The International Himalayan Expedition to Kanchenjunga and made the first ascent of Jonsang Peak, at that time the highest climbed summit. In 1932 he made first ascents of Chopicalqui, Copa and other summits in the Cordillera Blanca, Peru as a member of an Alpenverein expedition.
Hoerlin studied at the Institutes of Technology in Berlin and Stuttgart and took his Ph.D. degree at Stuttgart in 1936. For his doctoral research he made cosmic ray measurements over distances extending from Spitsbergen to the Straits of Magellan. During this work he established the highest earthbound cosmic ray observatory station at the summit of Nevado Copa in the Cordillera Blanca staying there for weeks by himself and subsequently making periodic solo ascents of the peak to collect data.
In 1938 he came to the U.S. as manager of the physics laboratory at General Aniline and Film Corporation in Binghamton, New York. Hoerlin joined the Los Alamos Scientific Laboratory in 1953 where he became leader of an outstanding group of scientists studying the phenomenology of nuclear explosions, especially those at high altitude.
Thus, professionally, as in climbing, Hoerlin achieved distinction in solving problems arising at high altitude. It is ironic that during the last year of his life he was handicapped by deteriorating lung function which forced him to move from Santa Fe, NM (7000 feet) to Massachusetts.
Hoerlin is survived by his wife, Kate, three daughters, 17 grandchildren, and 7 great grandchildren. He was a member of the American Alpine Club for many years.
George I. Bell