WHY WATER IS FOUND AT THE TOP OF MOUNTAINS.
>From the straits of Gibraltar to the Don is 3500 miles, that is one mile and 1/6, giving a fall of one braccio in a mile to any water that moves gently. The Caspian sea is a great deal higher; and none of the mountains of Europe rise a mile above the surface of our seas; therefore it might be said that the water which is on the summits of our mountains might come from the height of those seas, and of the rivers which flow into them, and which are still higher.
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.