Peter Abelard, in an interesting passage in the _Expositio in hexaemeron_,[843] gave an interpretation of this phrase as well as of the text about the “congregation of the waters” which seems to foreshadow a theory later to be elaborated by Brunetto Latino and destined to gain a firm grip on the hydrographical conceptions of many individuals until as late as the eighteenth century. Abelard wrote: “When the waters receded into one part of the earth, the other parts were uncovered, as was written: ‘God, who established the earth on the waters.’ As any globe may be immersed in water in such a way that one part of it rises above the water, even so the globe of the earth rests in the waters so that one side of it is contiguous with the sea and causes the sea to permeate through its veins, whence springs and rivers take their rise. The waters of this sea, in truth, are congregated into one place and are consequently deeper than if they were diffused, unless, perchance, the fact that they may be drawn off through the veins of the earth makes them less deep.” We have seen that Abelard and William of Conches compared the universe to an egg in which the four parts correspond to the four elements, fire, air, water, and earth.[844] This was the theoretical arrangement of the elements according to the logical application of Aristotle’s physical laws. As a matter of fact, the aqueous sphere does not completely envelop the earth, as it should if this theoretical arrangement were carried out in nature. How, then, could it be explained that a portion of the earth’s surface is not covered by water? Robert Grosseteste, without attempting a physical explanation, answered this question from the teleological point of view, echoing the words of Genesis. “Truly it is a fact,” he wrote, “that, in order that the animals of this earth might have a habitation and refuge, the water receded into the concave parts of the earth and the surface of the land appeared dry and distinct. And so the land with the waters contained upon it is like a sphere of earth.”[845] Later writers were not willing to accept such a simple declaration and looked for physical and mechanical explanations. For instance, Brunetto Latino assigned to the spheres of earth and of water each a different center, placed in such positions in relation to one another that the aqueous sphere covers the sphere of earth to a great depth on one side (the southern hemisphere) but on the opposite side leaves dry the portion inhabited by man.[846] Certainly the passage we have quoted above shows that Abelard may well have had something of this sort in mind. _THE OCEANS AND SEAS_ RELATIVE AREAS OF LAND AND SEA