When once created, what form did this universe take, and the earth within it? SPHERICITY OF THE UNIVERSE Nearly all the authors of our period appear to have shared in the belief that the universe is a sphere and that the earth is situated in its center. Lambert of St. Omer says in his _Liber floridus_: “We say the earth is the center, that is, the point in the middle of the sphere.” “For the earth is located as a central point in the midst of the celestial circle through which the sun passes.”[645] Robert Grosseteste stated that the sphericity of the universe was necessitated by the nature of the substances composing the heavenly bodies and that it could be proved by simple astronomical observations.[646] There is, perhaps, an echo of Pythagorean mathematical doctrines in the exposition which we find in the _Image du monde_, that the world is round since God desired it to be so, because roundness is the most perfect of all forms.[647] Al-Farghānī, whose work was translated more than once during our period and formed the basis of much that is found in John of Holywood’s _De sphaera_,[648] had said that there was no difference of opinion among learned men that the universe was a sphere. That the earth is in the center of the heaven, he asserted, was shown by the fact that half the heaven is always visible from all parts of its surface.[649] The author of the _De imagine mundi_ had also thought the same way:[650] he compared the universe to a ball, or to an egg of which the shell corresponds to the upper heavens, the white, to the upper air, the yolk, to the lower air, and the _pinguedinis gutta_, or drop of grease in the center, to the earth.[651] Gervase of Tilbury,[652] who borrowed the idea from Comestor,[653] and the author of the _Image du monde_[654] make similar comparisons, although Peter Abelard,[655] William of Conches,[656] and Daniel of Morley conceived of the four parts of the egg as corresponding exactly to the four elements.[657] Michael Scot compared the earth, surrounded by water, to the yolk of an egg and the spheres of the universe to the layers of an onion.[658]