The Collaborative International Dictionary of English v.0.48:

Bacon \Bacon\, Roger Bacon \Roger Bacon\prop. n.
   Roger Bacon. A celebrated English philosopher of the
   thirteenth century. Born at or near Ilchester, Somersetshire,
   about 1214: died probably at Oxford in 1294. He is credited
   with a recognition of the importance of experiment in
   answering questions about the natural world, recognized the
   potential importance of gunpowder and explosives generally,
   and wrote comments about several of the physical sciences
   that anticipated facts proven by experiment only much later.
   [PJC]

         The Franciscan monk, Roger Bacon (c. 1214 - 1294) was
         an important transitional figure in chemistry as he was
         trained in the alchemical tradition, but introduced
         many of the modern concepts of experimental science.
         Bacon believed that experiment was necessary to support
         theory, but for him the theory as presented in the
         Bible was true and the experiment only underlined that
         truth. One of Bacon's lasting contributions was his
         references to gunpowder, bringing this discovery to the
         general attention of literate Europeans.
         Gunpowder had been known for centuries in China, being
         used for fireworks and incendiary grenades. Gunpowder
         is a simple mixture of charcoal, sulfur, and potassium
         nitrate (known generally as saltpeter). Saltpeter is a
         major component of guano (bird droppings) and may be
         recovered from privies where it will crystallize. By
         1324, Europeans had discovered the art of using
         gunpowder to fire a projectile, marking the end of the
         period of castles and knights in armor.  --Prof. Tom
                                                  Bitterwolf,
                                                  Univ. of Idaho
                                                  (Post-class
                                                  notes, 1999).
   [PJC]

         Roger Bacon was Born at or near Ilchester,
         Somersetshire, about 1214: died probably at Oxford in
         1294. He was educated at Oxford and Paris (whence he
         appears to have returned to England about 1250), and
         joined the Franciscan order. In 1257 he was sent by his
         superiors to Paris where he was kept in close
         confinement for several years. About 1265 he was
         invited by Pope Clement IV. to write a general treatise
         on the sciences, in answer to which he composed his
         chief work, the "Opus Majus." He was in England in
         1268. In 1278 his writings were condemned as heretical
         by a council of his order, in consequence of which he
         was again placed in confinement. He was at liberty in
         1292. Besides the "Opus Majus," his most notable works
         are "Opus Minus," "Opus Tertium," and "Compendium
         Philosophiae." See Siebert, "Roger Bacon," 1861; Held,
         "Roger Bacon's Praktische Philosophie," 1881; and L.
         Schneider, "Roger Bacon," 1873.          --Century
                                                  Dict. 1906.
   [PJC]

         Dr. Whewell says that Roger Bacon's Opus Majus is "the
         encyclopedia and Novam Organon of the Thirteenth
         Century, a work equally wonderful with regard to its
         general scheme and to the special treatises with which
         the outlines of the plans are filled up.[sb] The
         professed object of the work is to urge the necessity
         of a reform in the mode of philosophizing, to set forth
         the reasons why knowledge had not made a greater
         progress, to draw back attention to the sources of
         knowledge which had been unwisely neglected, to
         discover other sources which were yet almost untouched,
         and to animate men in the undertaking by a prospect of
         the vast advantages which it offered.[sb] In the
         development of this plan all the leading portions of
         science are expanded in the most complete shape which
         they had at that time assumed; and improvements of a
         very wide and striking kind are proposed in some of the
         principal branches of study.[sb] Even if the work had
         no leading purposes it would have been highly valuable
         as a treasure of the most solid knowledge and soundest
         speculations of the time; even if it bad contained no
         such details it would have been a work most remarkable
         for its general views and scope."        --James J.
                                                  Walsh
                                                  (Thirteenth
                                                  Greatest of
                                                  Centuries,
                                                  1913.
   [PJC] Bacon

WordNet (r) 3.0 (2006):

Roger Bacon
    n 1: English scientist and Franciscan monk who stressed the
         importance of experimentation; first showed that air is
         required for combustion and first used lenses to correct
         vision (1220-1292) [syn: Bacon, Roger Bacon]