Cloudland; A Study on the Structure and Characters of Clouds (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 edition. Excerpt: ... CHAPTER V CHARACTERS AND CONTRASTS--CLOUDS OF INVERSION 51. Before proceeding with a detailed description of the clouds under this heading, it may be advisable, even at the price of repetition, to place before the reader the broad distinction in formation between these clouds and those dealt with in the previous chapter. This distinction is, that whereas clouds of Interfret are caused by the interaction of more or less horizontal currents of different velocities or directions, clouds of Inversion are caused by condensation in an upward direction in more or less vertical currents, although the shape of the clouds of the latter class may be affected by differences of velocity and direction in the horizontal movements of the air. Cumulo-rudimen turn 52. Many misleading titles, such as Fracto-cumulus and Cumulo-frustum, have been applied to this wellknown cloud, but these, as we shall see later, lead us to erroneously presuppose that the cloud is a brokendown and degraded form of Cumulus. The range of altitude of the rudimentary cloud is small. The mean altitude, as given in Table III., is 1500 feet (458 m.) above mean sea-level. But in reference to this variety of cloud it is important to observe that in the tropical and extra-tropical latitudes the level is higher in summer than in winter, and that the alteration of level is greater over the land than over the open sea, For the heating of the floor of the atmosphere causes vapour to remain in the state of vapour near that floor, and raises the level at which condensation is possible; and it is the atmosphere which exists over a land-surface which has its temperature specially raised by insolation, since the solid surface conducts less heat downward than the liquid, and parts with more heat...