The Pneumatics of Hero of Alexandria

nature does not permit. Therefore, given the vacuum, local movement cannot otherwise be made. Besides this, no operation can be attributed to the vacuum; therefore, it is not [existent], for if it were, nature would not permit it to remain idle, as it does not permit it to other things that have being.

With all this, our Hero holds a different opinion and strives to prove with reasons and sensible proofs that the vacuum is found disintegrated in various minute particles, scattered through the mass of other natural bodies, and that those particles of disintegrated vacuums can be reunited together with some violence. I do not believe that he does this because he had not seen what Aristotle wrote about it, who had already been in the world before him, and it was fitting that his writings be published; but rather because he found himself obliged to some other sect, or perhaps because with these principles it seemed to him that he could more easily save and render the reason for what was seen to happen around his Spirituals.

All the above-written divisions, definitions, and positions, and besides these few particularities of place, of motion, and of the vacuum, we have found it expedient to touch upon, but briefly, because they are like terms, and whoever possesses them well will understand much more easily the matter that is treated. But let us hear by now how Hero discourses regarding his vessels, which truly can be said to be similar to the Cup of Helen, which, as Homer relates, had the virtue of making others remember every trouble and annoyance.

A woodcut illustration depicts a symbolic ornament, possibly a floral or architectural motif, signifying the end of the introduction.