It was also in part in play - R. L. Stevenson's "The Sea Fogs"

Napa Valley was gone; gone were all the lower slopes and woody foothills of the range; and in their place, not a thousand feet below me, rolled a great level ocean.  It was as though I had gone to bed the night before, safe in a nook of inland mountains, and had awakened in a bay upon the coast.

Newlyweds Robert Louis Stevenson and Fanny Stevenson née Osborne, like many new couples, took their honeymoon in Napa Valley.  Tourists like other tourists, they explored a petrified forest and sampled Napa wine, “still in the experimental stage.”  The bed and breakfasts of 1880 were not what they are now, so the Stevensons set up house in the office of an abandoned silver mine on the side of Mount Saint Helena, overlooking Napa Valley.

Far away were hilltops like little islands.  Nearer, a smoky surf beat about the foot of the precipices and poured into all of the coves of these rough mountains.  The color of the fog ocean was a thing never to be forgotten.  For an instant, among the Hebrides and just about sundown, I have seen something like it on the sea itself.  But the white was not so opaline; nor was there, what surprisingly increased the effect, that breathless, crystal stillness over all.

The Stevensons lived on the mountainside because of R. L.’s lungs.  So many of his decisions were based on the state of his fragile, faulty lungs.  He certainly could not vacation on the Pacific shore:

It was to flee these poisonous fogs that I had left the seaboard, and climbed so high among the mountains.  And now, behold, here came the fog to besiege me in my chosen altitudes, and yet so beautifully that my first thought was of welcome.

Stevenson follows the path of an eagle over the fog.  He watches landmarks disappear into the rising sea.  He learns to identify the motion of the cloud.  He imagines that he is witnessing the flood of Genesis.

Had this been indeed been the deluge, I should have felt more strongly, but the emotion would have been similar in kind.  I played with the idea, as the child flees in delighted terror from the creations of his fancy.  The look of the thing helped me.  And when at last I began to flee up the mountain, it was indeed partly to escape from the raw air that kept me coughing, but it was also part in play.

This last idea – the sheer fun of the sublime – is the closest thing to an idea in Stevenson’s encounter with the salty fog.  Otherwise, “The Sea Fogs,” a seven page chapter of The Silverado Squatters, is just a piece of nature writing.  Stevenson watches the fog come in; he climbs the mountain to stay above it; a wind blows it out.  The metaphorical conceit is to confuse the fog with the sea itself, and look for incongruities – “the bough of a dead pine beckoned out of the spray like the arm of a drowning man.”

A marvelous piece of writing, almost my favorite of Stevenson’s, hidden in a little-known book.  But not unknown.  You can, if lucky, follow Stevenson’s path and see the fogs for yourself at Robert Louis Stevenson State Park in Napa and Sonoma counties.