Heronis Alexandrini spiritalium liber

If, therefore, someone blowing, and placing his hand to his mouth, immediately plugs the siphon with his finger, the air will remain compressed in the sphere for all time. But if someone opens it again, the air that was sent in will burst out with great noise and clamor; this is because, as we proposed, it is expelled by the dilatation of the pre-existing air, which was made by a certain impetus. Again, if someone wishes to draw out with his mouth through the siphon the air that is in the sphere, he will obtain a great quantity, with no other substance succeeding into the sphere, just as was said before regarding the egg. Wherefore, from this it is clearly shown that a great amassing of a vacuum has been made in the sphere. For the bodies of air that are left at that time cannot become larger so that they fill the place of the expelled bodies. For if they were increased while no substance reached them from the outside, it would be likely that the increase occurred through rarefaction. But this is entanglement according to evacuation. But they say there is no vacuum. Therefore, the bodies will not be increased; for neither can any