THE CIRRO-CUMULUS, OR SONDER-CLOUD.
The cirrus having continued for some time increasing or stationary, usually passes either to the cirro-cumulus or to the cirro-stratus, at the same time descending to a lower station in the atmosphere.
The Cirro-cumulus is formed from a cirrus, or a number of small separate cirri, passing into roundish masses, in which the extent of the cirrus is no longer to be seen. This change takes place either throughout the whole mass at once, or progressively from one extremity to the other. In either case the same effect is produced on a number of neighbouring cirri at the same time, and in
the same order. It appears, in some instances, to be hastened by the approach of other clouds.
The cirro-cumulus forms a very beautiful sky, exhibiting sometimes numerous distinct beds of small connected clouds floating at different heights. It is frequent in summer, and accompanies warm,
dry weather. On a fine summer’s evening the small masses which compose this cloud, are often well defined, and lying quite asunder, or separate from one another; and on this account the term sonder-cloud has been applied to this modification. The whole sky is sometimes covered with these small masses. They are occasionally, and more sparingly, seen in the intervals of showers, and in winter.
Bloomfield, in the following beautiful lines, has noticed the appearance of the sonder-cloud:—
“For yet above these wafted clouds are seen
(In a remoter sky still more serene)
Others, detach’d in ranges through the air,
Spotless as snow, and countless as they’re fair;
Scatter’d immensely wide from east to west,
The beauteous semblance of a flock at rest:
These, to the raptur’d mind, aloud proclaim
The mighty Shepherd’s everlasting name.”
This cloud may either evaporate or disappear, or it may pass to the cirrus, or sink lower and become a cirro-stratus. In stormy weather, before thunder, a cirro-cumulus often appears, composed of very dense and compact round bodies, in very close arrangement. When accompanied by the