And the Heaven of Venus may be compared to Rhetoric because of two properties: the one is the brightness of its aspect, which is most sweet to behold, far more than any other star; the other is its appearance, now in the morning, now in the evening. And these two properties are in Rhetoric: for Rhetoric is the sweetest of all Sciences, since it principally aims at sweetness. It appears in the morning, when the Rhetorician speaks before the face of the hearer; it appears in the evening, that is, afterwards, when it speaks by Letters in distant parts. And the Heaven of the Sun may be compared to Arithmetic because of two properties: the one is, that with his light all the other stars are informed; the other is that the eye cannot gaze at it. And these two properties are in Arithmetic, which with its light illuminates all its Sciences: for their subjects are all considered under some Number, and with Number one always proceeds in the consideration of these; as in Natural Science the movable body is the subject, which movable body has in itself three reasons of continuity, and this has in itself reason of infinite number. And of Natural Science its first and chiefest consideration is to consider the principles of natural objects, which are three, that is, matter, privation, and form; in which this Number is seen, and not only in all together, but again in each one, as he who considers subtly may perceive. Wherefore, Pythagoras, according to what Aristotle says in the first book of the Physics, established as the principles of natural things, the equal and the unequal; considering all things to be Number. The other property of the Sun is again seen in Number, of which Number is the Science of Arithmetic, that the eye of the intellect cannot gaze at it. For Number, inasmuch as it is considered in itself, is infinite; and this we cannot, understand.