Laboratory experiments have been performed to determine the rate of solution and the change in composition of air bubbles in stirred sea water as a function of depth (0-200 m) and temperature (1-27° C). At each depth the shrinking of the diameter is nearly linear. This rate of solution increases with increasing pressure up to a limiting value which is almost reached at a depth of 20 m. The rate of disappearance of a bubble is only imperceptibly influenced by temperature. When a bubble of air dissolves at a given depth it becomes richer in nitrogen until a final constant composition is reached. This final nitrogen percentage increases with increasing depth. Equations have been developed, based on the theory of diffusion, which satisfactorily account for the observed facts.