The two-dimensional natural convection flow arising from a long, finite size heat source located on a vertical or inclined plate is studied experimentally. Of particular interest were the nonboundary layer effects that arise in the flow, particularly in the neighborhood of the source, and the conjugate transport effects due to conduction into the plate. The dependence of these effects on the physical variables, such as heat input and size of the source, was studied. The plate was also inclined from 0 degree to 70 degree to study the nature of the flow that results, particularly any separation that may arise due to the increasing inclination between the plate and the vertical buoyancy force. Surface temperatures, along with the temperature distribution in the flow, were measured to characterize the flow and the transport mechanisms. Flow separation was observed at large inclinations, as expected, and was found to affect the transport near the separation region very substantially. The conduction into the plate was found to play a very important role in the distribution of the thermal field which, in turn, substantially affects the flow.