On the second day God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters; and he called the firmament Heaven.[Genesis 1:6-8.] God divided the firmament and made it movable; and he made other sensitive things comprehensible. And the waters that ran together he fixed in the nature of crystals, and he fastened the stars to them. Now the sphere of the heavens, with its fixed stars, is provided with two pivots, one of which is called the north, and the other the south pole, and is revolved from east to west with such speed that the world would be torn asunder if the planets in their counter-courses would not prevent it. The master-craftsman of the world so tempered the heavens with water that the heat of the upper regions cannot ignite the other elements. Some teachers, not only of our own time, but also among the Hebrews and others, believed that above the spheres of the seven planets, and above the eighth sphere, which they call the unerring one, and also over the ninth sphere, which is reached by reason alone and not by perception (and which is the first among movable corporeal things) is a tenth sphere, that is stationery and at rest. Consequently Isaac the Wise, one of the learned men already mentioned, holds that the tenth heaven was identified by Ezekiel through the zaphirum, in the similitude of a throne; and that the color of the zaphirum, the brilliance of the light and the likeness of a throne, indicated immobility. But to return to Moses, who separated the waters from the waters, resulting in a triple division of corporeal things under the moon! Some are in the middle region of the air as the uppermost part of the same element, as the brightest fire, and in itself a pure unmixed and proper element. Others are under the mid-regions of the air, as with us, where there is no pure element, but all elements are mixed, due to the density of the corporeal world. In between is a region of the air, also called the firmament, in which rain, snow, lightning, thunder, comets and the like appear. Therefore this firmament is very fitly distinguished, not alone because of its location, but because of its nature as well—the upper elements from the lower, as the water from the waters. Therefore the upper elements are pure and bright and separated from those below, which are mixed. And he called the firmament Heaven for it covered all susceptible and unseen things.

Schedel’s commentary on the work of the second day is very obscure. In medieval times the revolution of the spheres was not supposed to take place, like the motion of the earth in modern astronomy, round an imaginary axis, but round one which had a material existence, which was provided with pivots moving in fixed sockets. According to Vitruvius, architect to Augustus,

Many of Schedel’s commentaries are based upon the theories of Greek philosophers concerning the structure of the heavens. Thus Eudoxus, who paid more attention than others to the motions of the planets, gave more than one sphere to each of them to represent or account for variations of movement. According to his theory every planet has a separate part of heaven to itself, which is composed of several concentric spheres, whose movements, modifying each other, produce that of the planet. These concentric spheres were supposed to fit each other, so that the different planets were only separated by the thicknesses of these crystal zones.

In a small work ascribed to Aristotle, entitled Letter of Aristotle to Alexander on the System of the World, is the following passage:

Another passage of the same work states that,

The testimony of Ezekiel to which the text refers, was this: