During the period from 1963 through 1968 a series of instaneous and continuous release dye experiments were conducted in the near-shore coastal waters off southern California. The results of these experiments have been interpreted in terms of two- and three-dimensional apparent coefficients of eddy diffusivity. During the course of this investigation, little evidence was found to substantiate the applicability of the so-called four-thirds law relating the instantaneous apparent diffusivity coefficients and the approximate eddy scale. The findings cast doubt on the direct applicability of the four-thirds law in the design of submarine waste outfalls or in predicting the behavior of other low density surface fields. (Author Modified Abstract)