The Summary of Physics Restored

120Those who teach that earth and fire, the extreme bodies of this lower world, take one another’s places—assuming, without conceding, a sphere of fire—deceive themselves and mock the truth. Their natures are too far apart and too opposed to permit such interchange. Earth’s extreme coldness, grossness, and heaviness so oppose fire’s extreme heat, subtlety, and lightness that they do not allow a mutual conversion. Moreover, earth, being fixed, does not yield to fire and scorns its powers, if the opinions of chymists and common experience are to be trusted. Nothing flies off from it except an oily or watery moisture, both foreign to earth itself. If anything could change into elemental fire, it would have to become light and volatile so as to pass into fire’s sphere and nature. Since earth is the heaviest of all, and therefore the centre, and the most fixed of all, and therefore the least volatile, how can it change into fire and be raised into fire’s sphere? Or how can fire, the highest and lightest of all, be thrust down into earth against Nature’s laws and be essentially united with it? Water and fire would exchange more easily, because they are one degree closer than earth and fire.