Fixing credit for voltage measurements

In the section that I authored in “Sensing the Ocean” (PHYSICS TODAY, February 2011, page 24 ), I mistakenly attributed the voltage measurements on the submarine cable between Key West, Florida, and Havana, Cuba, solely to Henry Stommel. Actually, Gunther Wertheim was the first to observe and publish the measurements. ¹ He interpreted the voltages in terms of volume transports of the Florida Current. Stommel later published several papers based on Wertheim’s and other measurements on the submarine cable.

I am pleased to recognize the foundational role of Wertheim, who recently wrote to me, saying, “At the time I was a graduate student in nuclear physics at Harvard, but obtained one year’s worth of a more or less continuous record of that voltage after installing electrodes in the ocean near the Western Union Cable Huts at each end. WHOI [the Woods Hole Oceanographic Institution] provided the stable electrodes[;] Western Union made one of their spare cables available and provided space for the data acquisition, a chart recorder.”