a. (Physics & Chem.) See Dextrogyrate. [ 1913 Webster ]

n. [ From a proper name Roger. ] A black flag with white skull and crossbones, formerly used by pirates; -- called also Jolly Roger and pirate flag. [ Webster 1913 Suppl. +PJC ]

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. 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. 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. 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 ]