‹‹‹ Vitr. 8.2.2 | Table of Contents | Vitr. 8.2.4 ›››
3The vapours, clouds, and exhalations which rise from the earth, seem to depend on its retention of intense heat, great winds, cold moisture, and its large proportion of water. Thus when, from the coolness of the night, assisted by the darkness, winds arise, and clouds are formed from damp places, the sun, at its rising, striking on the earth with great power, and thereby heating the air, raises the vapours and the dew at the same time.
3That vapour, mists, and humidity come forth from the earth, seems due to the reason that it contains burning heat, mighty currents of air, intense cold, and a great quantity of water. So, as soon as the earth, which has cooled off during the night, is struck by the rays of the rising sun, and the winds begin to blow while it is yet dark, mists begin to rise upward from damp places. That the air when thoroughly heated by the sun can make vapours rise rolling up from the earth, may be seen by means of an example drawn from baths.