§ 1. Between the flocks of small countless clouds which occupy the highest heavens, and the gray undivided film of the true rain-cloud, form the fixed masses or torn fleeces, sometimes collected and calm, sometimes fiercely drifting, which are, nevertheless, known under one general name of cumulus, or heaped cloud.

The true cumulus, the most majestic of clouds, and almost the only one which attracts the notice of ordinary observers, is for the most part windless; the movements of its masses being solemn, continuous, inexplicable, a steady advance or retiring, as if they were animated by an inner will, or compelled by an unseen power. They appear to be peculiarly connected with heat, forming perfectly only in the afternoon, and melting away in the evening. Their noblest conditions are strongly electric, and connect themselves with storm-cloud and true thunder-cloud. When there is thunder in the air, they will form in cold weather, or early in the day.

§ 2. I have never succeeded in drawing a cumulus. Its divisions of surface are grotesque and endless, as those of a mountain; perfectly defined, brilliant beyond all power of colour, and transitory as a dream. Even Turner never attempted to paint them, any more than he did the snows of the high Alps.