I have already been to see a great variety (of atmospheric effects). And lately over Milan towards Lago Maggiore I saw a cloud in the form of an immense mountain full of rifts of glowing light, because the rays of the sun, which was already close to the horizon and red, tinged the cloud with its own hue. And this cloud attracted to it all the little clouds that were near while the large one did not move from its place; thus it retained on its summit the reflection of the sunlight till an hour and a half after sunset, so immensely large was it; and about two hours after sunset such a violent wind arose, that it was really tremendous and unheard of.
[Footnote: di arie is wanting in the original but may safely be inserted in the context, as the formation of clouds is under discussion before this text.]
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.