Just as eating against one's will is injurious to health, so studying without a liking for it spoils the memory, and it retains nothing it takes in.

One can have no more mastery over the environment, than one has over himself.

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.

... we might say that the earth has a spirit of growth; that its flesh is the soil, its bones the arrangement and connection of the rocks of which the mountains are composed, its cartilage the tufa, and its blood the springs of water.

Weight is caused by one element being situated in another; and it moves by the shortest line towards its centre, not by its own choice, not because the centre draws it to itself, but because the other intervening element cannot withstand it.

It is better to imitate ancient than modern work.

The eye which turns from a white object in the light of the sun and goes into a less fully lighted place will see everything as dark.