If a man has a tent made of linen of which the apertures have all been stopped up, and be it twelve bracchia across (over twenty-five feet) and twelve in depth, he will be able to throw himself down from any height without sustaining injury. [His concept of the parachute.]

A luminous body will appear more brilliant in proportion as it is surrounded by deeper shadow.

Fix your course on a star and you'll navigate any storm.

All our knowledge has its origins in our perceptions.

If you put on more garments, the cold cannot reach you. Similarly, increase your patience and concentration and even great injuries cannot vex your mind.

Love shows itself more in adversity than in prosperity; as light does, which shines most where the place is darkest.

The young man should first learn perspective, then the proportions of objects. Next, copy work after the hand of a good master, to gain the habit of drawing parts of the body well; and then to work from nature, to confirm the lessons learned.