Greyen

[…] he sometimes saw, between him and the ground, lightening the darkness, greyening the leaves and, in wet weather, tinseling the rain, a fascia of white light.

So Watt busied himself a little while, covering the lamp, less and less, more and more, with his hat, watching the ashes greyen, redden, greyen, redden, in the grate, of the range.