The painter who draws merely by practice and by eye, without any reason, is like a mirror which copies every thing placed in front of it without being conscious of their existence.

Experience, the interpreter between creative nature and the human race, teaches the action of nature among mortals: how under the constraint of necessity she cannot act otherwise than as reason, who steers her helm, teaches her to act.

Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.

When you put your hand in a flowing stream, you touch the last that has gone before and the first of what is still to come.

Now do you not see that the eye embraces the beauty of the whole world? It counsels and corrects all the arts of mankind... it is the prince of mathematics, and the sciences founded on it are absolutely certain. It has measured the distances and sizes of the stars it has discovered the elements and their location... it has given birth to architecture and to perspective and to the divine art of painting.

Where there is most feeling, there is the greatest martyrdom.

Necessity is the mistress and guide of nature.