still the bird took no heed, but at a slight movement instantly
scuttled back under the arch. The water-rat, less timorous, paused,
looked round, and returned to feeding.

Crossing to the other side of the bridge, up stream, and looking over,
the current had scooped away the sand of the bottom by the central pier,
exposing the brickwork to some depth--the same undermining process that
goes on by the piers of bridges over great rivers. Nearer the shore the
sand has silted up, leaving it shallow, where water-parsnip and other
weeds joined, as it were, the verge of the grass and the stream. The
sunshine reflected from the ripples on this, the southern side,
continually ran with a swift, trembling motion up the arch.

Penetrating the clear water, the light revealed the tiniest stone at the
bottom: but there was no fish, no water-rat, or moorhen on this side.
Neither on that nor many succeeding mornings could anything be seen
there; the tail of the arch was evidently the favourite spot. Carefully
looking over that side again, the moorhen who had been out rushed back;
the water-rat was gone. Were there any fish? In the shadow the water was
difficult to see through, and the brown scum of spring that lined the
bottom rendered everything uncertain.

By gazing steadily at a stone my eyes presently became accustomed to the
peculiar light, the pupils adjusted themselves to it, and the brown
tints became more distinctly defined. Then sweeping by degrees from a
stone to another, and from thence to a rotting stick embedded in the
sand, I searched the bottom inch by inch. If you look, as it were at
large--at everything at once--you see nothing. If you take some object
as a fixed point, gaze all around it, and then move to another, nothing
can escape.