A review of nearly a century’s research on the effects of heating a fluid from below in a body force field reveals many unusual aspects of the resulting flow which had previously been of meteorological interest only. For horizontal fluid layers, the flow was found to depend on a single parameter (the Rayleigh number). Below certain critical values of the Rayleigh number the configuration is in stable equilibrium; for Rayleigh numbers exceeding the critical either columnar or cellular flows occur with increased heat-transfer rates. It is pointed out herein that configurations with heating from below also are encountered in present-day problems in various fields. A recent experiment and an analysis of fluids heated from below in a vertical enclosure (which more closely simulates current configurations) are discussed and there appears to be a correlation between the previous research for meteorological purposes and new problems of current interest in fluid mechanics and heat transfer.