I suppose it was nearly seven when I once more mounted the platform to look abroad. The fog ocean had swelled up enormously since last I saw it; and a few hundred feet below me, in the deep gap where the Toll House stands and the road runs through into Lake County, it had already topped the slope, and was pouring over and down the other side like driving smoke. The wind had climbed along with it; and though I was still in calm air, I could see the trees tossing below me, and their long, strident sighing mounted to me where I stood.

Half-an-hour later, the fog had surmounted all the ridge on the opposite side of the gap, though a shoulder of the mountain still warded it out of our canyon. Napa Valley and its bounding hills were now utterly blotted out. The fog, sunny white in the sunshine, was pouring over into Lake County in a huge, ragged cataract, tossing treetops appearing and disappearing in the spray. The air struck with a little chill, and set me coughing. It smelt strong of the fog, like the smell of a washing-house, but with a shrewd tang of the sea salt.