I've been meaning to send in a note about this since I got back from my Aug. 12-19 trip to the park.    If I had to offer a single piece of F&M watching advice to the crowd that was watching event cycles that week, it would be this:  A lot of you are leaving way too early, and sooner or later, if Fan and Mortar get more frequent, you are going to find yourself just getting back to the Hamilton store as somebody calls the lock, and you're going to see the start from somewhere between Castle and Grotto.    To be clear:  Fan and Mortar are not "toast," as they were often characterized that week, just because the vents are not splashing continuously or voluminously.  I can recall maybe two eruptions out of the 50-odd I've seen from the start when Gold and High came on strong and stayed continuously strong until the start of the eruption.  In the vast majority of cases, they died down to comparatively minor splashing for five or ten minutes before coming back with high water levels and then continuous jetting.    In some cases, particularly in the early '90s when East Vent starts were common, Gold and High went entirely to steam for a while (five or ten minutes), only to recover suddenly and erupt 30 to 35 minutes after the start of River Vent.    I saw several event cycles in August where up to ten minutes after most gazers headed out because Gold and High stopped their early-cycle jetting, water levels recovered appreciably and held for several minutes.  Based on my experience, any one of those cases could easily have proceeded to a lock and eruption in minutes, and it wouldn't have been a case of "It's a geyser, it can do what it wants," it would have been a very typical build-up to eruption for the last 15 or more years. David Schwarz