When fogs come crafty down the mountainside

When fogs come crafty down the mountainside
And quell the summer's green in mumming mists,
Pulling light into their hill-killer blindness,
Then all my night's in new bright dark espied
And all I had thought hid in nightmares dead
Is come again unaccountable as cold,
A softly omnipresent nameless dread
That steals whatever warmth dawn had willed.

And blind again at dawn in the soulless cold,
I see my rapture-nightmares in brightness rolled
And confront the sourceless something of my soul:

Hill on hill within, revealing valley,
Valley, valley, does nothing to allay
My sense that sense itself must this nothing sully.