in time-wasting loops and diversions. Its changes of direction are frequently teasing: on its journey it heads at different times north, south, and west, as though it has forgotten its easterly destination--or put it aside for the while. At Ashton Keynes it splits into so many rivulets that every house in the village must have a bridge to its own front door; later, around Oxford, it takes a great unhurried detour around the city. It has other capricious tricks up its sleeve: in places it slows to drift lazily in wide pools before recovering its urgency and speeding on again. At Buscot it splits into twin streams to maroon a lengthy piece of territory, then regathers its water into a single channel. If this is hard to understand from a map, the rest is harder. For one thing, the river that flows ever onwards is also seeping sideways, irrigating the