Heronis Alexandrini spiritalium liber

those medical vessels original: "cucurbitulam" (cupping glasses) that consist of glass and have narrow mouths: when they wish to fill them with moisture, squeezing out the air which is contained in them with the mouth, and closing the mouth with a finger, they invert them into the moisture; and with the finger released, the water is attracted into the emptied place, and that same moisture is carried upward against its nature. And what happens around the cupping glass is not at all foreign to the things we have said. For when applied to the body, they not only do not fall off while having a manifest weight, but they attract the adjacent matter through the rarities of the body for the same reason: for the injected fire corrupts and thins the air which is contained in them, just as other bodies are corrupted by fire and changed into thinner substances. I speak, however, of air, water, and earth. For it is manifest that they are corrupted from the abandoned coals. For they, keeping the same mass which they had at the beginning before combustion, or a little smaller, differ greatly in weight. Those things which are corrupted in bodies pass through smoke into a fiery substance, and an airy, and an earthy. For those things which are thinner are in the...