Question regarding the paper by Sheeley et al. This is a very clear and simple paper really, but one major issue must arise after all our studies of the fast solar wind: 1. What is the difference between the slow and fast wind, if one accepts the assertion by the authors that the "blobs" they observe are passively advected by a Parker type pressure driven wind? Why such large differences in temperature and velocity between the slow and fast wind? Can you think of alternative physical models?