The Pneumatics of Hero of Alexandria

pulled to fill the vacuum place, and against its nature it ascends. And what is seen to happen with cupping glasses original: "ventose" is not different from this which we have said, for applied to the body, they do not fall, having apparent weight, but for the same reason they pull to themselves, through the rare parts of the body, the surrounding matter; because, having placed fire within, it makes the air that it finds there more rare, and corrupts it, just as it also destroys all other bodies and reduces them with its force into more pure substances, I mean of air, of water, and of earth, which are evidently known to be corrupted by way of extinguished coals, for while these maintain the same size that they had before they were burned, or slightly less, nevertheless, as to weight, they are very different, because those parts of the bodies that are corrupted pass through by means of smoke into the nature of fire, of air, of water, and of earth, for the lighter parts are transported into the most eminent place, where the sphere of fire is; those somewhat thicker into the air; the others, then, quite thick, which had been raised in part in the company of these, continuing the same motion, return again to the lowest place and rejoin themselves to the earthly parts. Likewise, water corrupted by fire is transformed into air, and the vapors that ascend from boiling vessels are nothing other than parts of water made thin, which already become air. However, how fire resolves every body that is more material than itself and transmutes it, from what has been said, clearly appears; and also from the exhalations that issue from the earth, which transmute thicker bodies into thinner and purer things, for the dews do not otherwise rise on high if the water that is among the earth is not first refined by means of exhalation. Of this exhalation, the cause is a certain substance of a fiery nature, produced by the sun, which while it passes through the earth warms that place, and so much the more if it holds sulfur or bitumen, which, once heated, generates many exhalations; and the hot waters that spring from the earth are such for this same reason. The thinner parts of the dew are transmuted into air, and the thicker ones, having been raised somewhat by the force of the exhalation, when it then cools due to the departure of the sun, are again led back down by their own