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In his interesting article, “TRIP Illumines Lightning” [Eos, Vol. 67, May 20, 1986], Hill has performed a valuable service by bringing together and discussing over two dozen of the various mechanisms that have been proposed to explain the origin of the electrical energy responsible for lightning. It is worth noting, however, that this article perpetuates some misconceptions that continue to interfere with a satisfactory understanding of thunderstorms. Following Chalmers [1967], Hill divides explanations of electrification into two classes: those that rely on gravitation and those that do not. He mistakenly places theories that transport charge by convection instead of by falling precipitation into the non-gravitational class. It should be recognized, however, that the mechanisms that carry charge by updrafts and downdrafts depend on gravity just as much as those that carry charge by falling precipitation particles.