It is, of course, an illusion to imagine that the crossing of arbitrary boundaries on a map should correspond to variations in mood and temperament. A field is a field and a tree is a tree, but nevertheless this could only be France, and the air on the train took on a different quality, or seemed to, as French passengers emanated the satisfaction of returning home, and the rest of us the excitement of being officially ‘abroad’. ‘Here we are then! France!’