You should look at certain walls stained with damp, or at stones of uneven color. If you have to invent some backgrounds you will be able to see in these the likeness of divine landscapes, adorned with mountains, ruins, rocks, woods, great plains, hills and valleys in great variety; and expressions of faces and clothes and an infinity of things which you will be able to reduce to their complete and proper forms. In such walls the same thing happens as in the sound of bells, in whose stroke you may find every named word which you can imagine.

What is fair in men, passes away, but not so in art

He who wishes to be rich in a day will be hanged in a year.

The desire to know is natural to good men.

As every divided kingdom falls, so every mind divided between many studies confounds and saps itself.

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

When you draw a nude, sketch the whole figure and nicely fit the members to it and to each other. Even though you may only finish one portion of the drawing, just make certain that all the parts hang together, so that the study will be useful to you in the future.