Scientific Theories in the 1800's

After reading Ch. 21, do some online research into scientific theories in the 1800's (19th Century). Find at least one theory that you can see has a direct connection to the visual arts. Briefly outline the theory (include the thinkers behind it) and pick a work from your text (note the page number) that you feel demonstrates this theory. Explain specifically how your chosen work demonstrates this scientific theory. What style is your work?