Coincidently with the creation of the original _materia_ the universe had assumed a rotary motion,[600] each complete rotation marking a day. In the further unrolling of the universe, fire was the active element (_artifex et efficiens causa_), earth the passive element, and air and water stood as intermediaries between fire and earth. During the first rotation, or first day, the fire heated and illumined the inferior elements in such a manner as to cause the air to be released from them (_aer ex inferioribus elementis spissatus_), and thus the atmosphere came into existence.[601] On the second day the fire, by illuminating the air, transmitted heat to the third element, water, which rose in the form of clouds. Some of this vaporized water ascended so high that it passed into the second heavenly sphere, where it became the “waters above the firmament,” the firmament itself, according to Theodoric, being the atmosphere.[602] So much water in this manner was absorbed out of the original _materia_ that inevitably on the third day the earth appeared like islands in the midst of the waters remaining behind. Theodoric compared these to islands that are formed when water dries after it has been spilled upon a table. Immediately the heat of the atmosphere was mingled with the humors of the earth, and the latter thereby received the power of producing vegetable life, herbs and trees. On the fourth day the stars were formed out of the waters which had been drawn above the firmament. On the fifth day the heat of the universe brooded over (_incubuit_) the waters of the earth’s surface and gave birth to fish and birds. Finally, on the sixth day, the life-giving heat reached the earth; and from it the animals were created, including, of course, man.[603] _William of Conches’ Theory_