Book excerpt: "Lectures on Art, Delivered Before the University of Oxford in Hilary Term, 1870" is a compilation of lectures for visual art students by John Ruskin, a 19th-century art critic. He lectured at Oxford University on a variety of topics, including art. In the lectures, Ruskin discussed the importance of lines, shadow, and colors and analyzed the works of the Greek school of light and the Gothic school of color.