His writings are one long tirade against ignorance. He told his age it was ignorant, an incredibly bold thing to do. Nowadays a man may tell the world it is as silly as it is solemn, that all its methods are still infantile and clumsy and its dogmas childish assumptions, without much physical danger; but these peoples of the middle ages when they were not actually being massacred or starving or dying of pestilence, were passionately convinced of the wisdom, the completeness and finality of their beliefs, and disposed to resent any reflections upon them very bitterly. Roger Bacon’s writings were like a flash of light in a profound darkness. He combined his attack upon the ignorance of his times with a wealth of suggestion for the increase of knowledge. In his passionate insistence upon the need of experiment and of collecting knowledge, the spirit of Aristotle lives again in him. “Experiment, experiment,” that is the burthen of Roger Bacon. Yet of Aristotle himself Roger Bacon fell foul. He fell foul of him because men, instead of facing facts boldly, sat in rooms and pored over the bad Latin translations which were then all that was available of the master. “If I had my way,” he wrote, in his intemperate fashion, “I should burn all the books of Aristotle, for the study of them can only lead to a loss of time, produce error, and increase ignorance,” a sentiment that Aristotle would probably have echoed could he have returned to a world in which his works were not so much read as worshipped—and that, as Roger Bacon showed, in these most abominable translations. AN EARLY PRINTING PRESS AN EARLY PRINTING PRESS _(From an old print) _ Throughout his books, a little disguised by the necessity of seeming to square it all with orthodoxy for fear of the prison and worse, Roger Bacon shouted to mankind, “Cease to be ruled by dogmas and authorities; _look at the world!_” Four chief sources of ignorance he denounced; respect for authority, custom, the sense of the ignorant crowd, and the vain, proud unteachableness of our dispositions. Overcome but these, and a world of power would open to men: — “Machines for navigating are possible without rowers, so that great ships suited to river or ocean, guided by one man, may be borne with greater speed than if they were full of men. Likewise cars may be made so that without a draught animal they may be moved _cum impetu inœstimable_, as we deem the scythed chariots to have been from which antiquity fought. And flying machines are possible, so that a man may sit in the middle turning some device by which artificial wings may beat the air in the manner of a flying bird.” So Roger Bacon wrote, but three more centuries were to elapse before men began any systematic attempts to explore the hidden stores of power and interest he realized so clearly existed beneath the dull surface of human affairs.