=198.= Air on its downward path changes to water. This change is described as due to loss of heat[47], and yet water too has some heat and vitality[48]. Even earth, the lowest and grossest of the elements, contains a share of the divine heat; otherwise it could not feed living plants and animals, much less send up exhalations with which to feed the sun and stars[49]. Thus we may say even of a stone that it has a part of the divinity in it[50]. Here then we see the reverse side of the so-called Stoic materialism. If it is true that God is body, and that the soul is body, it is equally true that even water, the damp and cold element, and earth, the dry and cold element, are both penetrated by the divinity, by the creative fire without the operation of which both would fall in an instant into nothingness[51]. [Sidenote: The heavenly bodies.] =199.= We return to the consideration of the heavenly bodies. These are set in spheres of various diameter, all alike revolving around the earth. The succession we find described in Plato’s _Timaeus_[52]; the moon is nearest to the earth, then comes the sun, then in order Venus, Mercury, Mars, Jupiter and Saturn. This theory was taken up by Aristotle and after him by Eudoxus, from whom it passed to Aratus and Chrysippus[53]. A tradition derived from Chaldaean sources gave a different order, setting Venus and Mercury nearer to the earth than the sun; and this order was accepted by the middle Stoics, that is to say by Panaetius and Posidonius, the latter placing Venus nearer to the earth, and therefore further from the sun, than Mercury[54]. The moon, like the earth, obtains her light from the sun, being crescent-shaped when nearest to him, full-orbed when furthest away. Her distance from the earth is two million stadia (250,000 miles); when she lies between the earth and the sun she eclipses his light, but when she is on the side of the earth directly away from the sun she is herself eclipsed[55]. Her phases are explained by her position relative to the sun[56]. The sun is 60 millions of miles from the earth[57]; his diameter is 37½ times as large as that of the earth[58]; he appears larger when on the horizon because his rays are refracted through the thick atmosphere[59]. The planets, whether they revolve round the earth or the sun, are falsely called ‘wandering stars,’ since their orbits have been fixed from all eternity[60]. The fixed stars revolve round the earth at such a distance that the earth, when compared with it, is merely the central point[61]. All the heavenly bodies are, like the earth, of spherical form[62]. Finally Seneca, in advance of the school, declared the comets to be a regular part of the celestial world[62a]. [Sidenote: Cruder theories.]