4 probably Mexico’s most famous chemist. It is an interesting aside, for me at least, that Pancho Villa briefly ‘invaded’ the US at Columbus, NM, which is almost due north of Colonia Juarez. With the reluctant agreement of the Mexican government, General Pershing was sent on an unsuccessful expedition to capture Villa; Colonia Dublan was his headquarters and his guides were some of the local Mormons. However, Henry had left by then and missed this adventure. enrolled as a PhD student in chemistry at the University of California in Berkeley in 1925. After graduation, he spent two years engaged in teaching and research at the University of Wisconsin in Madison. There he met and in 1928 married his first wife, Mildred Bennion. They had three sons, Edward (Ted), Henry B. (Hal), and Harden. Mildred died in 1969. During her illness that extended over five years, Henry faithfully cared for her and was with her when she died. A few years after Mildred’s death, he married Winifred Brennan, adopting her youngest daughters. Henry attended the University of Arizona in 1919. He obtained a BSc and MSc in mining and metallurgical engineering. I, too, had a (mercifully) brief career in underground (copper) mining. Eyring decided that a mining/metallurgy career was not for him and he III. BERLIN AND PRINCETON After a short period back at Berkeley, he joined the faculty at Princeton, where he stayed until 1946. There he produced many important results. He developed his famous reaction Following his stay in Wisconsin, in 1929 he was awarded a post doctoral fellowship to work at the Kaiser Wilhelm Institute in Dahlem in southwestern Berlin. Curiously, my parents lived in Dahlem for a time, as members of the diplomatic corps, while I was a doctoral student of Eyring. Eyring’s original plan was to work with Bodenstein but, perhaps fortunately, Bodenstein was away and he collaborated with Michael Polanyi. Quantum mechanics was in its infancy and there was much to be done. Quantum me- chanics had not yet been applied to study reactions. Eyring and Polanyi 7 chose to study the simplest reaction, the replacement reaction, H + H$_{2}$ −→ H$_{2}$ + H by applying the Heitler- London method, including exchange. This was one of the first applications of quantum mechanics to obtain an energy surface for a reaction and, in my opinion, this was one of his most significant papers.