Book 8
3.3
And I (Ammonius bidding me oppose him) said: Sir, your suppositions which require a vacuum to be granted I shall admit; but you err in supposing that a vacuum is conducive either to the preservation or conveyance of sound. For that which cannot be touched, acted upon, or struck is peculiarly favorable to silence. But sound is a stroke of a sounding body; and a sounding body is that which is homogeneous and uniform, easy to be moved, light, smooth, and, by reason of its tenseness and continuity, obedient to the stroke; and such is the air. Water, earth, and fire, are of themselves soundless; but each of them makes a noise when air falls upon or gets into it. And brass hath in it no vacuum; but being mixed with a smooth and gentle air it answers to a stroke, and is sounding. If the eye may be judge, iron must be reckoned to have a great many vacuities, and to be porous like a honey-comb, yet it is the dullest, and sounds worse than any other metal.
