Thales affirms that they are globes of earth set on fire. Empedocles, that they are fiery bodies arising from that fire which the aether embraced within itself, and did shatter in pieces when the elements were first separated one from another. Anaxagoras, that the circumambient aether is of a fiery substance, which, by a vehement force in its whirling about, did tear stones from the earth, and by its own power set them on fire, and establish them as stars in the heavens. Diogenes thinks they resemble pumice stones, and that they are the breathings of the world; again he supposeth that there are some invisible stones, which fall sometimes from heaven upon the earth, and are there quenched; as it happened at Aegos-potami, where a stony star resembling fire did fall. Empedocles, that the fixed stars fastened to the crystal, but the planets are loosened. Plato, that the stars for the most part are of a fiery nature, but they are made partakers of another element, with they are mixed after the resemblance of glue. Zenophanes, that they are composed of inflamed clouds, which in the daytime are quenched, and in the night are kindled again. The like we see in coals; for the rising and setting of the stars is nothing else but the quenching and kindling of them. Heraclitus and the Pythagoreans, that every star is a world in an infinite aether, and encompasseth air, earth, and aether; this opinion is current among the disciples of Orpheus, for they suppose that each of the stars does make a world. Epicurus condemns none of these opinions, for he embraces anything that is possible. CHAPTER XIV. OF WHAT FIGURE THE STARS ARE. The Stoics say that the stars are of a circular form, like as the sun, the moon, and the world. Cleanthes, that they are of a conical figure. Anaximenes, that they are fastened as nails in the crystalline firmament; some others, that they are fiery plates of gold, resembling pictures. CHAPTER XV. OF THE ORDER AND PLACE OF THE STARS. Xenocrates says that the stars are moved in one and the same superficies. The other Stoics say that they are moved in various superficies, some being superior, others inferior. Democritus, that the fixed stars are in the highest place; after those the planets; after these the sun, Venus, and the moon, in order. Plato, that the first after the fixed stars that makes its appearance is Phaenon, the star of Saturn; the second Phaeton, the star of Jupiter; the third the fiery, which is the star of Mars; the fourth the morning star, which is the star of Venus; the fifth the shining star, and that is the star of Mercury; in the sixth place is the sun, in the seventh the moon. Plato and some of the mathematicians conspire in the same opinion; others place the sun as the centre of the planets. Anaximander, Metrodorus of Chios, and Crates assign to the sun the superior place, after him the moon, after them the fixed stars and planets. CHAPTER XVI. OF THE MOTION AND CIRCULATION OF THE STARS.