The lover is moved by the beloved object as the senses are by sensual objects; and they unite and become one and the same thing. The work is the first thing born of this union; if the thing loved is base the lover becomes base.

I have always felt it is my destiny to build a machine that would allow man to fly.

The mind that engages in subjects of too great variety becomes confused and weakened.

Every action done by nature is done in the shortest way.

Every action needs to be prompted by a motive.

Shadow is the diminution alike of light and of darkness, and stands between darkness and light.

Ask advice of him who governs himself well.