Note 6 — Chapter I

If a stone be comparatively soft when quarried and become harder after exposure to the air, this is due to the elimination in the air of moisture that it held when in the earth. In a dry climate like that of Egypt there is little or no moisture for stones to hold, and the Egyptian porphyry, Mr W. Brindley reports, is quite as hard when freshly quarried as after exposure. Vasari repeats this remark when he is dealing with granite in § 6, postea, p. 41. He has derived it from Alberti, who in De Architectura, bk. II, ch. vii, notices perfectly correctly that the question is one of the comparative amount of moisture in the stone.