Vitruvius - Air Quotes 14 Sourced Quotes
If one of these elements, heat, becomes predominant in any body whatsoever, it destroys and dissolves all the others with its violence.... Again if too much moisture enters the channels of a body, and thus introduces disproportion, the other elements, adulterated by the liquid, are impaired, and the virtues of the mixture dissolved. This defect, in turn, may arise from the cooling properties of moist winds and breezes blowing upon the body. In the same way, increase or diminution of the proportion of air or of the earthy which is natural to the body may enfeeble the other elements. Vitruvius
In the states of Maxilua and Callet, in Further Spain, as well as in Pitane in Asia Minor, there are bricks which, when finished and dried, will float on being thrown into water. The reason why they can float seems to be that the clay of which they are made is like pumice-stone. So it is light, and also it does not, after being hardened by exposure to the air, take up or absorb liquid.... They have therefore great advantages; for they are not heavy to use in building and, once made, they are not spoiled by bad weather. Vitruvius