Of the moon. The moon has no light of its own, except that, as much of it as the sun sees, so much does it illuminate; and of that luminosity we see as much as is the part that sees us. And its night receives as much splendour as our waters lend it in reflecting back to it the image of the sun, which is mirrored in all those waters that see both sun and moon. The skin, or surface, of the water of which the sea of the moon and the sea of our earth is composed is always wrinkled, whether little or much, more or less; and such roughness is the cause of dilating the innumerable images of the sun, which are mirrored in the hills and hollows and sides and fronts of the innumerable wrinkles — that is, in as many various sites of each wrinkle as there are various sites of the eyes that see them. This could not happen if the sphere of water that in great part clothes the moon were of uniform sphericity, for then the image of the sun would be single to each eye, and its reflection particular, and there would always be a spherical splendour, as the gilded balls set on the summits of tall buildings plainly teach us. But if such gilded balls were rough or globular, like mulberries — black fruits composed of minute round globosities — then each part of those globosities seen by the sun and by the eye would show to that eye the lustre generated by the image of that sun. And thus in one and the same body many least suns would be seen, which often, over a long distance, unite and appear continuous. The lustre of the new moon is brighter and more powerful than when it is at the full; and this is caused because the angle of incidence is much more obtuse in the new moon than in the old, where such angles are most acute; and the waves of the moon mirror the sun both in their valleys and on their hills, while the sides remain dark. But at the sides of the moon the depths of the waves do not see the sun, only the crests of those waves see it, and for this the images are rarer and more mingled with the shadows of the valleys. And such mingling of the shadowy and luminous species, thus fused together, come to the eye with little splendour, and at the edges they will be darker, because the curvature of the sides of such waves is insufficient to reflect the received rays to the eye. So the new moon by nature reflects the solar rays more toward the eye by such edge-waves than by any other place, as the figure of the moon shows: [two figures with letters] striking with the rays a on the wave b, it reflects them at b d where the eye d is situated. And this cannot happen at the full moon, where the solar ray, being at the west, strikes the edge-waves of the moon at the east from n to m, and does not reflect toward the western eye, but rebounds to the east, bending little the straightness of that solar ray: and thus the angle of incidence is very large.

The innumerable images that reflect from the innumerable waves of the sea, from the solar rays striking upon those waves, are the cause of rendering a continuous and very broad splendour over the surface of the sea.

The moon is an opaque and solid body; and if, as the adversary holds, it were transparent, it would not receive the light of the sun.

The yolk of the egg stands in the middle of its white without descending to any side, and it is either lighter, or heavier, or equal to that white: and if it is lighter, it ought to rise above all the white and stop in contact with the shell of the egg; and if it is heavier, it ought to descend; and if it is equal, it could as well stand at one of the extremes as in the middle or below.