CITATION BY L. L. SLOSS; Award of the Penrose Medal, the Society's highest honor; to Robert M. Garrels, marks the 49th time that the Council of the society has taken such action since the award was established in 1927. Between the first recipient, T. C. Chamberlin, and Bob Garrels the average age of medalists has remained surprisingly constant, decaying at a rate of about 56 days per year, and thus will not drop below 60 until the second decade of the next century. Those who have beaten the chronologic statistics have been clearly identifiable specialists and theorists such as Norman Bowen and George Simpson; generalists (Bailey Willis and Foster Hewitt, for example) tend to achieve the Society's recognition somewhat later in their careers. Bob Garrels is both specialist and genera-list and, as an inevitable consequence, falls very close to the Penrose regression line.
Garrels professional career began in a manner that R.A.F. Penrose, Jr. would have applauded, that is, Bob's early work concerned such matters as the lead-zinc deposits of the Mississippi Valley and the chromite of the Stillwater Complex: Thirty-odd years ago, when I first became associated with him, he was already-deeply involved in minerals, solutions, and equilibria at near-surface pressures and temperatures. It has never been made clear whether this specialization was arrived at by deep intellectual choice or by reason of the fact that his laboratory equipment, dominated by Skippy peanut-butter jars, placed severe constraint on the P/T realms available for investigation. In any case, Garrels, the specialist, evolved, courses were developed, students emerged, books were written and published, and peer recognition was attained as documented by the G.S.A. Day Medal and the Geochemical Society's Goldschmidt Award.