The Pneumatics

existing together with the vessel, it is plunged into the water; then, the vessel being uncovered and having its mouth upward, let the water enter. The air indeed departs from the vessel; but being overcome by the great quantity of water, it is again mixed and intervolved, so that it becomes water. In the same manner, the air in a cupping-glass being consumed and rarefied by fire, and having escaped through the pores of the vessel, the place made empty within attracts the surrounding matter, of whatever kind it be. But when the cupping-glass has recovered, the air succeeds into the evacuated place, and the matter is no longer attracted. Those, therefore, who assert universally that there is no vacuum at all, may devise many arguments for these things, and perhaps persuade more by their discourse, although they bring forward no sensible demonstration. But if it shall be shown in those things which are manifest and fall under the senses, that a massed vacuum is produced contrary to nature, but that a vacuum exists by nature disseminated in small parts, and that bodies themselves by compression fill these disseminated vacua, those who bring forward plausible reasons concerning these matters are by no means to be listened to any longer.