in different classes of bodies, and his appeal to his own preconceived ideas of "nature" to prove what exists, or does not exist, outside the circumference of Heaven, are very characteristic.
Time and Space, then, according to Aristotle, end with the circumference of Heaven, though it is difficult to understand how space can he conceived to come to an end at any particular point. But the Stagirite here becomes mystical, for he says that, "the things outside," existing in neither space nor time, enjoy for all eternity a perfect life of absolute joy and peace ('Heavens,' I. ix.) This is the region of the divine, in which there is life and consciousness, though perhaps no personality; it is increate, immutable, and indestructible.
Descending from this region—if that can be called region which is out of space altogether—we come in the Aristotelian system to the "First Heaven," the place of the fixed stars, which ever revolves with great velocity from the left to the right. In a lower sphere, revolving in the contrary direction, are the sun, moon, and planets; and we are told that we must not suppose that either stars or planets are composed of fire. Their substance is ether, that fifth element, or quinta essentia, which enters also into the composition of the human soul. They only seem bright, like fire, because the friction caused by the rapidity with which they are carried round makes them red-hot. The reason why the stars twinkle, but the planets do not, is merely that the former are so far off that our sight reaches them in a weak and trembling condition; hence their light
