The Pneumatics

can any other increase be conceived as happening to them. From which it is clear that certain voids are disseminated between the bodies of air, and that when a certain force is applied, these bodies are forced, contrary to nature, into the voids. Moreover, the air which is in a vessel inverted into water is not greatly compressed; for that which applies the force to effect this is least suited to it, since water naturally has neither weight nor strong compression within itself. Wherefore it happens that divers in the depths of the sea, though they have infinite metretes of water above their shoulders, are not compelled by the water to exhale, even though a very small amount of air is contained in their nostrils. Furthermore, the cause why those who swim in the deep, as has been said, are not compressed despite having an infinite weight of water upon their shoulders, seems worthy of consideration. Some, therefore, say it is because water is of equal weight within itself; but these say nothing as to why those who swim below are not compressed by the water above. This, therefore, may be demon-