Here the thick fingers of the wings are those which hold the bird firm on the air against the motion of the wind. That is, the wind moves, upon which the bird, without beating its wings, sustains itself, and the bird does not change its place. The reason is that the bird arranges its wings at such obliquity that the wind, which strikes it from below, does not make for it a wedge of a nature that would raise it, but it does indeed raise it by just as much as its weight would wish to sink. That is, if the bird wishes to sink with a power of 2, the wind would wish to raise it with another power of 2; and because things equal among themselves do not overcome one another, the bird remains in its place without rising or descending. It remains to speak of the motion that drives it neither forward nor backward; and this is: if the wind wished to accompany it, or rather to push it out of its place, with a power of 4, and the bird, with the same power, leaning by the said obliquity against that wind, here too, the powers being equal, such a bird will not move forward, nor be driven backward, the wind remaining steady. But because the motions and powers of the winds are changeable and the obliquity of the wings must not be changed, for if the wind increases and it undid the obliquity, then, not being pushed upward by that wind ...

a. The wind does not, in the aforesaid cases, enter as a wedge beneath the oblique wings, but only finds the wing edge-on, which wishes to descend against the wind. Whence it strikes it on the edge of the shoulder (omere), which shoulder makes a shield to all the rest of the wing; and here the descent of the wing would have no defence, were it not for its thick thumb a, which then makes a front and receives in itself the whole force of the wind in the face, or in less than the face, according to the greater or lesser power of the wind.

Snow will be carried in summer to hot places, taken from the high peaks of the mountains, and let fall in the festivals of the piazzas in summertime.