Comparison of equivalent widths (EW) for N iiiλ4097 and λλ4640/42 for models with different nitrogen abundances and wind-strengths. Black diamonds: [N] = 7.78, mass-loss rates as in Table 1. Red triangles: as black diamonds, but with half the mass-loss rate. Purple squares: [N] = 8.18, mass-loss rates as in Table 1. Blue asterisks: as purple squares, but with half the mass-loss rate. All background abundances are solar (Asplund et al. 2005).