that he is thinking not only of the foam of the semen but of other widely different kinds of prolific foam as well? Does he not seem to think that, in general, the power of bringing matter to life as a new individual dwells typically in a bubble representing earth, water, and air, and charged with soul and with generative heat, for the presence of which the sun is responsible, heat other than that of elemental fire?[320] It is not fanciful--for Aristotle himself, we remember, has done so incidentally--to connect such speculation with the ancient myth of Aphrodite, the goddess of love, who sprang from the foam which had risen upon the sea, about the immortal genitals of Uranus, which had been severed and cast therein; Uranus being the heavens personified.[427] Before the time of Aristotle important thinkers had held the heavenly bodies, and even the heavens themselves, to be fire;[428] and we have seen that after his time Cleanthes did the same, simply setting apart the generative fire from the destructive. Aristotle denied that the sun is fire, though he could not have denied that its radiant generative heat produces no different sensation from that of sterile fire kindled upon earth. He did not identify the sun's heat with ether, the "body on high," though he styled the heat of the semen a "body" analogous to the ether. How then did Aristotle obtain heat from the ethereal sun? The point is crucial and he met it; but in so doing he revealed a very weak place in his towering fabric of speculation. In his treatise On Heaven, speaking of the heavenly bodies, he says:-- "The heat and light from these arise from the friction which the air undergoes by reason of their course. For it is the nature of motion to fire even wood and stone and steel." He then speaks of projectiles, and says:-- "These, then, are heated because borne onward in air which becomes fire from the shock of the motion. But each of the bodies on high is borne onward in its sphere, so that they are not fired; while the air, being beneath the sphere of the circling body,[429] is heated of necessity as this [body] is borne onward, and mainly where the sun is set in place. Therefore, when the sun approaches and rises and is above us, heat is generated. Be it said, then, of the heavenly bodies, that neither are they fiery nor are they borne on in fire."[430] In his Meteorology Aristotle boldly says: "The sun, which is held to be especially hot, appears white, but not to be like fire."[431]