FOGS AND CLOUDS
291
In either case, the individual droplets are quickly evaporated, and the cloud form preserved, only through continuous condensation from renewed air. It is permanent in the same sense that a cataract is permanent through the continuous supply of water by the stream above.

FIG.   97.—Crest cloud, windward side, seen from the Pali, near Honolulu.    (A. M. Ham-rick, photoar anker.}

FIG.   98.— Crest cloud, lee side, seen from Honolulu.    (A. M. Hamrick, photographer.)
Banner Cloud.—The banner cloud (Fig. 99), as its name implies, resembles a great white flag floating from a high mountain peak. In strong winds the pressure to the immediate leeward of such a peak is,