Compendium of All Natural Science

of the earth. Philosophers have indeed maintained that those surfaces by which the boundaries of the container and the contained are joined together are equal, for the reason that they should not be compelled to admit that any vacuum intervenes.

All bodies, however, are either surrounded by some place, as Jupiter is by Saturn, or they are believed to be equally distant from the center of the earth, like that ultimate heaven, beyond which it is proved that there is either nothing at all or a most pure void.

Indeed, all the elements tend toward the surface of the containing body. The earth, however, descends downward toward that which holds the center.

27. On the vacuum.

Indeed, some have thought that a vacuum exists, because some things are indeed extended, while others are compressed. This would not seem possible to be achieved unless a void (as the most delightful poet Lucretius says) were mixed within things, into which each thing might be received. But they did not see correctly that when some things are condensed or rarefied, thinner bodies can be both repelled and received, by which fact a thing appears either larger or smaller. For in rarefaction, not a new magnitude but a new place is acquired. For that is compressed which, though it may appear of small quantity, yet lies hidden under a greater amount of matter. Conversely, that is extended which, though it may appear of wide quantity, is yet enclosed under a smaller amount of matter. Of bodies, however, some, although they become both rare and dense,