The surface rearrangement of nickel and platinum due to (1) an electric field (build‐up) and (2) surface tension (annealing) as the net driving force, has been studied by field‐electron emission microscopy over the temperature range 510°–750°K for Ni and 550°–850°K for Pt. An Arrhenius‐type relationship between temperature and time was found in both cases, so that an activation energy could be associated with each process. It is assumed that this is an average activation energy for surface diffusion.The results of the field build‐up experiments gave an activation energy ofQf=19.1±1.9 kcal/mole for Ni over the negative field range (28–38)×106V/cm, andQf=26.3±2.6 kcal/mole for Pt over the negative field range (27–39)×106V/cm. It was possible to measure the effect of the electric field using a method devised earlier by Bettler and Charbonnier. This gave calculated zero‐field activation energies of 20.6±2.1 kcal/mole for Ni and 29.7±3.0 kcal/mole for Pt. The results of the annealing experiments (no electric field) gave an activation energy ofQ0=21.4±2.1 kcal/mole for Ni and 29.5±3.0 kcal/mole for Pt. (The foregoing indicated uncertainties are estimated over‐all limits of error.) It is concluded from the agreement between the results of the two different types of measurement that either type of measurement (for fcc metals) may be used to determine the same quantity within a 10% uncertainty.