It is sometimes said that Friar Bacon indulged in scientific speculations which seemed subversive of {329} Christian mysteries, and that this was one reason for his punishment. Recently he has been declared the first of the modernists since he attempted to rationalize religious mysteries. Whatever truth there may be in this, of one thing we are certain, that before his death Bacon deeply regretted some of his expressions and theories, and did not hesitate to confess humbly that he was sorry to have even seemed to hint at supposed science contrary to religious truth. Of course, it may well be said, even after all these communities of interest between the medieval and the modern teaching of the general principles of science have been pointed out, that the universities of the Middle Ages did not present the subjects under discussion in a practical way, and their teaching was not likely to lead to directly beneficial results in applied science. It might well be responded to this, that it is not the function of a university to teach applications of science, but only the great principles, the broad generalizations that underlie scientific thinking, leaving details to be filled in in whatever form of practical work the man may take up. Very few of those, however, who talk about the purely speculative character of medieval teaching, have manifestly ever made it their business to know anything about the actual facts of old-time university teaching by definite knowledge, but have rather allowed themselves to be guided by speculation and by inadequate second-hand authorities, whose dicta they have never taken the trouble to substantiate by a glance at contemporary authorities on medieval matters, much less by reading the old scholastics themselves. How much was accomplished in applied science during the Middle Ages, that is, in those departments of science {330} which are usually supposed to have been least cultivated, since educators are prone to ridicule the over-emphasis of speculation in education and the constant preoccupation of mind of the scholars of these generations with merely theoretic questions, may be appreciated from any history of the arts and architecture during the thirteenth, fourteenth, and fifteenth centuries. Some of the most difficult problems in mechanics as applied to the structural work of cathedrals, palaces, castles, fortresses, and bridges, were solved with a success that was only equaled by the audacity with which they were attempted. Men hesitated at nothing. There is no problem of mechanical engineering as applied to structural work which these men did not find an answer for in their wonderful buildings. This has been very well brought out by Prince Kropotkin in certain chapters of his book, Mutual Aid a Factor of Evolution, [Footnote 41] in which he treats of mutual aid in the medieval cities. He says: [Footnote 41: New York, McClure, Philips & Co., 1902.]