The Formation of Cumuli

Abstract

THIS afternoon the air to a great distance above the surface of the earth has been filled with fluttering dry leaves. For some weeks no rain has fallen in this vicinity, and a cold northerly wind has prevailed. To day, for the first time during the continuance of this cold and rather clear weather, the hill-sides having a southern exposure have begun to be sufficiently warmed to cause upward currents of air along their surface. The effect has been curious: piles of cumuli have formed persistently in certain quarters of the sky, and eddying masses of leaves caught up along the hill-sides have been falling apparently from the under surface of the dense masses of cloud. My attention was first caught by the fall of chestnut and other varieties of leaves, which must have traversed a long distance, as there are no trees of the sort near at hand in the direction from which the wind was blowing at the time. Whilst walking near an elevated ridge of ground an hour later it was my fortune to catch sight of a thick mass of leaves rushing directly up its side and pouring apparently into the bosom of a dark cloud which overhung the hill. This cloud remained almost stationary, although there appeared to be a lively breeze along its under surface, the leaves darting forward very swiftly. The entire phenomenon was quite interesting as affording an illustration of the method of formation of clouds of the variety named.