And in this it bears a great resemblance to Physics, if these three members, namely, two and twenty and a thousand, are carefully considered; for by the two is understood the local movement, which of necessity is from one point to another; and by the twenty is signified the movement of modification; for, inasmuch as from the ten upwards we proceed only by modifying this ten with the other nine, and with itself, and the most beautiful modification which it receives is that with itself, and the first which it receives is twenty, consequently the movement aforesaid is signified by this number. And by the thousand is signified the movement of increase; for in name this thousand is the greatest number, and cannot increase except by multiplying itself. And Physics show these three movements only, as is proved in the fifth chapter of its first book. And on account of the Galaxy this heaven has great resemblance to Metaphysics. For it must be known that of this Galaxy the philosophers have held diverse opinions. For the Pythagoreans said that the Sun once wandered out of his path; and, passing through other parts not adapted to his heat, he burned the place through which he passed, and the appearance of the burning remained there.