More than three centuries before Francis Bacon advocated the experimental method, Roger Bacon practised it, and the results as now revealed are wonderful. He wrought with power in philosophy and in all sciences, and his knowledge was sound and exact. By him, more than by any other man of the middle ages, was the world put on the most fruitful paths of science--the paths which have led to the most precious inventions. Among them are clocks, lenses, burning specula, telescopes, which were given by him to the world, directly or indirectly. In his writings are found formulæ for extracting phosphorus, manganese, and bismuth. It is even claimed, with much appearance of justice, that he investigated the power of steam. He seems to have very nearly reached also some of the principal doctrines of modern chemistry. But it should be borne in mind that his method of investigation was even greater than these vast results. In the age when metaphysical subtilizing was alone thought to give the title of scholar, he insisted on _real_ reasoning and the aid of natural science by mathematics. In an age when experimenting was sure to cost a man his reputation, and was likely to cost him his life, he insisted on experiment and braved all its risks. Few greater men have lived. As we read the sketch given by Whewell of Bacon's process of reasoning regarding the refraction of light, he seems fairly inspired.[96] On this man came the brunt of the battle. The most conscientious men of his time thought it their duty to fight him, and they did it too well. It was not that he disbelieved in Christianity; _that_ was never charged against him. His orthodoxy was perfect. He was attacked and condemned, in the words of his opponents, "_propter quasdam novitates suspectas_." He was attacked, first of all, with that goodly old missile, which, with the epithets "infidel" and "atheist," has decided the fate of so many battles--the charge of magic and compact with Satan. He defended himself with a most unfortunate weapon--a weapon which exploded in his hands and injured him more than the enemy, for he argued against the idea of compacts with Satan, and showed that much which is ascribed to demons results from natural means. This added fuel to the flame. To limit the power of Satan was deemed hardly less impious than to limit the power of God.[97] The most powerful protectors availed him little. His friend Guy Foulkes having been made pope, Bacon was for a time shielded, but the fury of the enemy was too strong. In an unpublished letter, Blackstone declares that when, on one occasion, Bacon was about to perform a few experiments for some friends, all Oxford was in an uproar. It was believed that Satan was let loose. Everywhere were priests, fellows, and students rushing about, their garments streaming in the wind, and everywhere resounded the cry, "Down with the conjurer!" and this cry, "Down with the conjurer!" resounded from cell to cell and hall to hall.[98]