Subsequent comparisons proved that her doze might have lasted for half an hour or more, before a sudden movement of the punt roused her with a start. She sat up, blinked sleepily around, and discovered to her surprise that the punt had moved from its anchorage and drifted into the centre of the stream. It had appeared so safely moored against the tree that she was puzzled to understand how this had come about, but as the movement had roused her from sleep she was glad that it had occurred, and, seating herself steadily, lifted her paddle to work her way back to the jetty. As she settled herself, however, Darsie's attention was arrested by the manner in which the banks seemed to be slipping past; she turned her head over her shoulder, and discovered that in the minute which had elapsed since she had awakened from sleep the willow-tree had been left several yards behind. Some mysterious change seemed to have passed over the surface of the still, almost stagnant, waters; they were flowing as with a tide, the rippling movement stirring the weedy banks. Darsie used her paddle automatically, but its puny force seemed superfluous, for the punt was moving of itself, quickly and still more quickly, swinging broadside to the stream in defiance of her efforts to keep it straight. Darsie ceased to struggle and leaned forward on the paddle to consider the situation. Then, for the first time, she became aware that the former stillness of the stream was replaced by a harsh, continuous noise, which seemed momentarily to increase in volume. What could it be? She stared around with puzzled eyes, but there was no hint of alarm in her bewilderment. A child of the city, she was inured to sudden and inexplicable noises; it was only when the punt swung heavily round a bend that she realised the seriousness of her position. The mill was working! One of the infrequent experimental trials of which she had heard was even now in process, the great moss-covered wheel was revolving creakily on its axle, waking the sleeping river into life, and the heavy punt was bearing down, more and more rapidly towards the crazy wooden gates!