Heronis Alexandrini spiritalium liber

if we make the entry with great force, the vessel will be broken before it receives anything while it is full; for the bodies of air cannot be contracted into a smaller size. Wherefore, it will be necessary that they have within themselves certain intervals into which, being compressed, they may occupy a smaller bulk. But this is not likely, with no vacuum at all existing, and when bodies are applied to each other along all surfaces, and likewise to the circumference of the vessel, they cannot, when expelled, make a place anywhere, with no vacuum existing. Wherefore, in no way will any of those things which are outside be sent into the sphere, unless some part of the air previously contained in it departs, if indeed the whole place is packed and continuous as they think. But if someone, moving the siphon to his mouth, wishes to blow into the sphere, he will send in much spirit, without the air that is in it departing. Since this always happens in this way, it is manifestly shown that a contraction of the bodies existing in the sphere occurs into the disseminated vacuums. But contraction occurs against nature due to the violence of the entry.