We show that whereas the critical point is very sensitive to the range of interaction, the second virial coefficient has a fairly constant value at the critical temperature. This enables us to predict the critical temperature with fair accuracy. We discuss the connection between the second virial coefficient as a predictor for the critical temperature and the second virial coefficient as predictor in crystal growth as was proposed by George and Wilson [A. George and W. W. Wilson, Acta Crystallogr., Sec. D: Biol. Crystallogr. 50, 361 (1994)]. (C) 2000 American Institute of Physics. [S0021-9606(00)51212-4].