My first true winter walk is perhaps that which I take on the river, or where I cannot go in the summer. It is the walk peculiar to winter . . .

  There is now, at 2.30 P.M., the melon-rind arrangement of the clouds. Really parallel columns of fine mackerel sky, reaching quite across the heavens from west to east, with clear intervals of blue sky, and a fine-grained vapor like spun glass extending in the same direction beneath the former. In half an hour all this mackerel sky is gone . . .

  Now that the river is frozen we have a sky under our feet also. Going over black ice three or four inches thick, only reassured by seeing the thickness at the cracks, I see it richly marked internally with large whitish figures suggesting rosettes of ostrich-feathers or coral . . .