Tribute to Roger Revelle and his contribution to studies of carbon dioxide and climate change.

I first came to Scripps Institution of Oceanography (SIO) in the summer of 1939, after completing my junior year at the California Institute of Technology. Roger Revelle was 30 years old, with the rank of instructor (long since abolished by the University of California), and a lieutenant junior grade in the Naval Reserve. Roger invited me to come along on an experiment to measure currents in the waters over the California borderland. The standard tool was an Ekman Current Meter; for every 100 revolutions of a propeller, a 2-mm ball is dropped into a compass box with 36 compartments, each corresponding to a 10° segment in current direction. The trouble was that the balls would not fall into the compartments. Roger was up all night doggedly fussing with the current meter until, at breakfast time, the release was functioning. This is my earliest memory of Roger.