When I sit down to make a sketch from nature, the first thing I try to do is to forget that I have ever seen a picture.

I never saw an ugly thing in my life.

A sketch will not serve more than one state of mind & will not serve to drink at again & again — in a sketch there is nothing but the one state of mind — that which you were in at the time.

The world is wide; no two days are alike, nor even two hours; neither were there ever two leaves of a tree alike since the creation of the world; and the genuine productions of art, like those of nature, are all distinct from one another.

Painting is a science, and should be pursued as an inquiry into the laws of nature. Why, then, may not landscape painting be considered as a branch of natural philosophy, of which pictures are but the experiments?

There has never been a boy painter, nor can there be. The art requires a long apprenticeship, being mechanical, as well as intellectual.

I do not consider myself at work unless I am before a six-foot canvas.