Evangelista Torricelli

"Is it a surprise that into the vessel, in which the mercury has no inclination and no repugnance, not even the slightest, to being there, it should enter and should rise in a column high enough to make equilibrium with the weight of the external air which forces it up?"

"Sola enim Geometria inter liberales disciplinar acriter exacuit ingenium, idoncumque reddit ad civitates exornandas in pace et in bello defendendas: caeteris enim paribus, ingenium quod exercitatum sit in Geometrica palestra, peculiare quoddam, et virile robur habere solet: praestabitque semper, et antecellet, circa studia architecturae, rei bellicae, nauticaeque, etc."

"Many have argued that a vacuum does not exist, others claim it exists only with difficulty in spite of the repugnance of nature; I know of no one who claims it easily exists without any resistance from nature."

"If this same balance, even though corporeal, were considered to be not on the earths surface but in the highest regions beyond the suns sphere, then the threads, while still drawn to the centre of the earth, would be very much less convergent to each other, would be quasi-parallel. Let us imagine a mechanical balance transported beyond the starry balance [i.e., the constellation of that name] in the firmament, to an infinite distance. It will be understood by everybody that the suspension threads would no longer be convergent, but would be exactly parallel. ... The Geometer has the special privilege to carry out, by abstraction, all constructions [operationes] by means of the intellect. Who, then, would wish to prevent me from freely considering figures hanging on a balance imagined to be at an infinite distance beyond the confines of the world?"