Roger Bacon, a major proponent of experimental science, has from 1247 to 1257 devoted himself wholeheartedly to the cultivation of those new branches of learning to which he had been introduced at Oxford—languages, optics, and alchemy—and to further studies in astronomy and mathematics.

The first European to describe in detail the process of making gunpowder, he fails to speculate further, though he knoes that, if confined, it will have great power and might be useful in war. (Its use in guns will arise early in the following century.)

Bacon has described spectacles (which also will soon come into use); elucidated the principles of reflection, refraction, and spherical aberration; and proposed flying machines and mechanically propelled ships and carriages.

He has used a camera obscura (which projects an image through a pinhole) to observe eclipses of the Sun.

He becomes a Franciscan friar in 1257; his outspokenness and unorthodox opinions are to involve him in frequent difficulties with the superiors of his order.