The original theoretical equation derived by Fowler and Nordheim has, for the last 80 years, influenced the way that experimental CFE data has been plotted and analyzed. In the very widely used Fowler–Nordheim plot, as introduced by Stern et al. in 1929, the quantity ln{ i / V } is plotted against 1/ V. The original thinking was that (as predicted by the original or the elementary Fowler–Nordheim-type equation) this would generate an exact straight line of slope S FN. S FN would be related to the parameters that appear in the exponent of a Fowler–Nordheim-type equation of i - V form by: