‹‹‹ Vitr. 1.6.1 | Table of Contents | Vitr. 1.6.3 ›››
2Wind is a floating wave of air, whose undulation continually varies. It is generated by the action of heat upon moisture, the rarefaction thereby produced creating a continued rush of wind. That such is the case, may be satisfactorily proved by observations on brazen æolipylæ, which clearly shew that an attentive examination of human inventions often leads to a knowledge of the general laws of nature. Æolipylæ are hollow brazen vessels, which have an opening or mouth of small size, by means of which they can be filled with water. Previous to the water being heated over the fire, but little wind is emitted, as soon, however, as the water begins to boil, a violent wind issues forth. Thus a simple experiment enables us to ascertain and determine the causes and effects of the great operations of the heavens and the winds.
2Wind is a flowing wave of air, moving hither and thither indefinitely. It is produced when heat meets moisture, the rush of heat generating a mighty current of air. That this is the fact we may learn from bronze eolipiles, and thus by means of a scientific invention discover a divine truth lurking in the laws of the heavens. Eolipiles are hollow bronze balls, with a very small opening through which water is poured into them. Set before a fire, not a breath issues from them before they get warm; but as soon as they begin to boil, out comes a strong blast due to the fire. Thus from this slight and very short experiment we may understand and judge of the mighty and wonderful laws of the heavens and the nature of winds.