the sun's pull at different points along the moon's path-takes 173.3 days to complete. This perturba- tion is in turn part of an 18.6 year "in-out" lunar oscillation perpendic- ular to the moon's orbit. England's chronically cloudy weather, argues EllegArd, would have prevented enough sightings to firmly establish the wobble's regularity. The region, although dryer and 2OC warmer 5,000 years ago, probably enjoyed only one clear day out of every two or three. Further, roughly one-third...