John Ruskin,
The Storm-Cloud of the Nineteenth Century
“ And yet observe: that thin, scraggy, filthy, mangy, miserable cloud, for all the depth of it, can't turn the sun red, as a good, business-like fog does with a hundred feet or so of itself. By the plague-wind every breath of air you draw is polluted, half round the world; in a London fog the air itself is pure, though you choose to mix up dirt with it, and choke yourself with your own nastiness.Now I'm going to show you a diagram of a sunset in entirely pure weather, above London smoke. ”
