NICHOLAS' COPERNICUS 125 kept in mind throughout any careful study of his theory, that it was an hypothe- sis framed to remove difficulties connected with older systems ; that he sought to bring conceptions of the universe into harmony with reason, instead of giving way to impressions made by the senses, or to the authority of world-hon- ored teachers, either in other days or in his own ; nor can we omit adding that, while he found fault with the Ptolemaic cycles and epicycles, he constructed sim- ilar devices of his own. " As the real motions, both of the earth and the planets, are unequable, it was requisite to have some mode of representing their inequalities ; and accordingly the ancient theory of excentrics and epicycles was retained so far as was requi- site for this purpose." In the case of Mercury's orbit he makes suppositions which are extremely complex, although they manifest his apprehension of the difficulties attendant on the common theory of his own time ; but he verified many of his views by astronomical observations ; and his approximations to mod- ern science, and the light he threw on preceding discoveries, establish the fame of Nicholas Copernicus. On a review of the life of Copernicus, and the conclusions he reached, the mental and moral qualities of the man come out with conspicuous and extraordi- nary lustre. He was a mathematician, thus walking in the footsteps of Roger Bacon. This science, since the days of Euclid, had been pursued with untiring ardor, and many who neglected to study, or who, by their own imagination, distorted the actual phenomena of nature, addicted themselves to the investigation of the abstract properties of magnitude and number. Copernicus, in his knowledge of mathematical principles, and in his skilful application of them to astronomical inquiries, probably surpassed all his contemporaries. And, at the same time, he had that inventive genius which is fruitful in suggestions, such as become pio- neers in the path of scientific demonstration. His independence of mind, his real originality, and his boldness in the pursuit of truth are quite as remarkable as the qualities just noticed ; indeed, they are involved in or they led to the latter of these. " I beg you," says one of his admiring disciples, " to have this opinion concerning that learned man, my preceptor, that he was an ardent admirer and follower of Ptolemy ; but when he was compelled by phenomena and demonstra- tion, he thought he did well to aim at the same mark at which Ptolemy had aimed, though with a bow and shaft very different from his." We must recollect that Ptolemy says ' He who is to follow philosophy must be a freeman in mind.' Copernicus knew very well that there were many prepared to challenge his con- clusions, and perhaps to bring theological objections to the principles of science which he had been constrained to adopt. " If, perchance," it is said in the preface to his book on astronomy, " there ber vain babblers who, knowing nothing of mathe- matics, yet assume the right of judging, on account of some place of Scripture, perversely wrested to their purpose, and who blame and attack my undertaking, I heed them not, and look upon their judgments as rash and contemptible." Copernicus had a profound reverence for Scripture. He regarded it as the
