Experimental work with thermally unstable air and liquids (Mal, 1931; Graham, 1933; Chandra, 1937; and others) has shown that the convection "cells" formed vary with the amoun t of shear, which is introduced either by the fl.ow of the fluid or by the movement of its boundaries. Changes in the flight tactics of free soaring gulls over the open ocean show that the pattern of the convectional up-fl.ow within air moving over warmer water varies with the wind speed (Woodcock, 1940). Since the air over warmer sea water moves in a fashion in part comparable to the experimental findings, it was thought that some similar motion might be observed in the water itself.