The ocean as a chemical system.

This discussion may have given the feeling that the present composition of ocean water does not result just from blind chance. The composition may in the main be given by well-defined equilibria, and the deviations from equilibrium may be explainable by welldefined processes. However, much remains to be discovered by laboratory work and studies of the natural systems. For any discussion of equilibria between sediments and sea water to become really fruitful and decisive, one must achieve a much better separation of the various sediment phases than has been obtained hitherto. Equilibrium data for various silicate systems are highly desirable. Studies of various elements indicate that there are serious gaps in our knowledge of soluble species and of equilibrium constants for known species; equilibrium measurements in the ionic medium, sea water, are scarce and not too reliable. Obviously, better understanding of the system ocean plus air plus sediments and of its history will require close cooperation between geologists, biologists, and chemists of various specialties.