During the course of an investigation of solar coronal heating, we were motivated to consider magnetic reconnection of the atmospheric magnetic field as a possible resistive heating source in the topological-dissipation model proposed by Parker (1972). It was apparent that a quantitative diagnostic was needed which could establish the existence of three-dimensional magnetic reconnection and provide quantitative information on the extent of its dissipative effects. A new diagnostic of general magnetic reconnection (GMR), as described by Schindler et al. (1988), is derived and applied to numerical simulations of the tearing mode and Alfv¿n waves. MHD simulations of Parker's heating model are then described, and the existence of reconnection is shown through the use of the GMR diagnostic and other indicators of magnetic reconnection. ¿American Geophysical Union 1995