Interactions between the separate natural convection flows induced by individual surfaces in a close spaced array are studied for various arrangements of spacing and orientation. The effects on heat transfer and on the induced flow and temperature field are determined. The causes of various effects are inferred from interferograms of the near temperature field and the rising plume. Certain relations between effects are apparent and are explicable in direct physical terms, although no analysis is given. It is clear from these results that interaction effects may be profitably optimized for particular ends. © 1969.