in Thoreau’s Journal:

These spring impressions (as of the apparent waking up of the meadow) are not repeated the same year, at least not with the same force, for the next day the same phenomenon does not surprise us, our appetite has lost its edge. The other day the face of the meadow wore a peculiar appearance, as if it were beginning to wake up under the influence of the southwest wind and warm sun, but it cannot again this year present precisely that appearance to me.

 I have taken a step forward to a new position and must see something else. We perceive and are affected by changes too subtle to be described.