All objects transmit their image to the eye in pyramids and the nearer to the eye these pyramids are intersected the smaller will the image appear of the objects which cause them.

An artist who lacks the power of self-criticism accomplishes but little. It is good if your work stands higher than your own opinion of it; bad if it is on the same level. But it is a great disaster if your work stands lower than your judgment of it.

The days are long enough for those who use them.

Truth was always but the daughter of time.

The length of a man's outspread arms is equal to his height.

I roamed the countryside searching for the answers to things I did not understand. Why shells existed on the tops of mountains along with the imprints of coral and plant and seaweed usually found in the sea. Why the thunder lasts a longer time than that which causes it and why immediately on its creation the lightening becomes visible to the eye while thunder requires time to travel. How the various circles of water form around the spot which has been struck by a stone and why a bird sustains itself in the air. These questions and other strange phenomena engaged my thought throughout my life.

A bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements.