The light and heat of the universe comes from the sun, and its cold and darkness from the withdrawal of the sun.

Those who condemn the supreme certainty of mathematics feed on confusion, and can never silence the contradictions of the sophistical sciences which lead to eternal quackery.

That which has no limitations, has no form.

The boundaries of bodies are the least of all things.

Any color is more distinctly seen when opposed to its contrary: thus, black on white, blear near yellow, green near red, and so on.

Blinding ignorance does mislead us. O! Wretched mortals, open your eyes!

I have discovered that a screw-shaped device such as this, if it is well made from starched linen, will rise in the air if turned quickly.