BACON, Roger, English monk and philos opher: b. near Ilchester about 1214; d. 1294. He first entered the University of Oxford, and afterward went to that of Paris, where he seems to have distinguished himself much by successful study and teaching, and received the degree of doctor of theology. About 1250 he returned to England, where he entered the order of Franciscans, fixed his abode at Ox ford, and devoted himself to his studies in natural philosophy, chiefly in alchemy, chem istry and optics. Means were furnished him by .generous friends of science, whose contri butions enabled him to purchase boolcs, to pre pare instruments and to make the• necessary experiments. In examining the secrets of nature he made discoveries and deducted re sults which appeared so extraordinary to the ignorant, that they were believed to be works of magic and he was brought under suspicion as a dealer in the black art. There is clear evidence in his writipgs that he accepted the Aristotelian theory of stellar influence on the minds and wills of men, not indeed directly, but through the medium of the body. Such views brought him into conflict with the teach ings of the Church on free will, and in 1257 he was sent to Paris, where he was kept in con finement for 10 years. In 1267 Bacon wrote a work under the title of 'Opus Majus,)— see article following—giving a connected view of the different branches of human knowledge, supplemented soon after by two other works, namely, 'Opus Secundum' and 'Opus-Tertium.) Under Clement's successor, Nicholas III, the general of the Franciscans, Jerome of Ascoli, declared himself against Bacon, forbade the reading of his writings, and issued an order for his imprisonment, which was confirmed by the Pope. This new confinement lasted from 1278 92; and when Jerome of Ascoli was elected Pope, under the name of Nicholas IV, Bacon vainly endeavored to convince him of the in nocence and utility of his labors, by sending .
him a treatise 'On the Means of Avoiding the Infirmities of Old Age.) After the death of Nicholas IV he regained his liberty, and re turned to Oxford, where he wrote a 'Com pendium of Theology' (1292).
Though an extraordinary man, Bacon was a child of his age, and not free from current errors. fie believed in the philosopher's stone and in astrology. There are to be found in his writings new and ingenious views on optics; for example, on the refraction of light, on the apparent magnitude of objects, on the magnified appearance of the sun and moon when in the horizon, etc. He describes very exactly the nature and effects of convex and concave lenses, and spealcs of their application to .the purposes of readingt and of viewing distant objects, both terrestnal and celestial; and it is easy to prove from his writings that he was either the inventor or improver of the tele scope. He also gives descriptions of the camera obscurg, and Of the burning-glass. He alio made several medical discoveries. The disr covery of gunpowder has been attributed to him. His writings contain the chemical for mula for it, but it is generally supposed that he obtained it from the Arabs, from whose writ ings he derived other suggestions. He was acquainted with geography and astronomy, dis covered the errors of the calendar and their causes, and made a corrected calendar. In moral philosophy, also, Bacon laid down some excellent precepts. His principal works, edited by Professor Brewer, were published in his 'Opera Inedita) (1859).