Quelli che s’innamorano della pratica senza la scienza, sono come i nocchieri che entrano in naviglio senza timone o bussola, che mai hanno certezza … - Leonardo da Vinci

I believe man will fly and I base this assumption on the fact that God has blessed us with minds that are capable of imagining it. Anything that can be dreamt of will eventually be built. Anyone who says otherwise is a fool.
(As quoted by a fictional Leonardo in DaVinci Demons)

That the atmosphere attracts to itself, like a lodestone, all the images of the objects that exist in it, and not their forms merely but their nature may be clearly seen by the sun, which is a hot and luminous body. All the atmosphere, which is the all-pervading matter, absorbs light and heat, and reflects in itself the image of the source of that heat and splendor and, in each minutest portion, does the same. The north pole does the same as the lode stone shows; and the moon and the other planets, without suffering any diminution, do the same.

In many cases one and the same thing is attracted by two strong forces, namely Necessity and Potency. Water falls in rain; the earth absorbs it from the necessity for moisture; and the sun evaporates it, not from necessity, but by its power.