Tides
The tide, as Geoffrey Chaucer observed, waits for no man. Even out at sea, when all seems calm on the surface, the tide is there, constantly changing, flooding in and then ebbing away. Remorseless and powerful, its effect is most dramatic close to the shore. For sailors, knowing the state of the tide can make the difference between passing harmlessly over an obstruction, or being wrecked on it. Between reaching the sanctuary of a port in a storm, or spending hours waiting for
