  The finite-size scaling algorithm based on bulk and surface renormalization
of de Oliveira (1992) is tested on q-state Potts models in dimensions D = 2 and
3. Our Monte Carlo data clearly distinguish between first- and second-order
phase transitions. Continuous-q analytic calculations performed for small
lattices show a clear tendency of the magnetic exponent Y = D - beta/nu to
reach a plateau for increasing values of q, which is consistent with the
first-order transition value Y = D. Monte Carlo data confirm this trend.
