The method of investigating truth by observation and experiment, so successfully pursued in the Principia, has been ascribed by some modern writers of great celebrity to Lord Bacon; and Sir Isaac Newton is represented as having owed all his discoveries to the application of the principles of that distinguished writer. One of the greatest admirers of Lord Bacon has gone so far as to characterize him as a man who has had no rival in the times which are past, and as likely to have none in those which are to come. In a eulogy so overstrained as this, we feel that the language of panegyric has passed into that of idolatry; and we are desirous of weighing the force of arguments which tend to depose Newton from the high-priesthood of nature, and to unsettle the proud destinies of Copernicus, Galileo, and Kepler. That Bacon was a man of powerful genius, and endowed with varied and profound talent,—the most skilful logician,—the most nervous and eloquent writer of the age which he adorned, are points which have been established by universal suffrage. The study of ancient systems had early impressed him with the conviction that experiment and observation were the only sure guides in physical inquiries; and, ignorant though he was of the methods, the principles, and the details of the mathematical sciences, his ambition prompted him to aim at the construction of an artificial system by which the laws of nature might be investigated, and which might direct the inquiries of philosophers in every future age. The necessity of experimental research, and of advancing gradually from the study of facts to the determination of their cause, though the groundwork of Bacon’s method, is a doctrine which was not only inculcated but successfully followed by preceding philosophers. In a letter from Tycho Brahe to Kepler, this industrious astronomer urges his pupil “to lay a solid foundation for his views by actual observation, and then by ascending from these to strive to reach the causes of things;” and it was no doubt under the influence of this advice that Kepler submitted his wildest fancies to the test of observation, and was conducted to his most splendid discoveries. The reasonings of Copernicus, who preceded Bacon by more than a century, were all founded upon the most legitimate induction. Dr. Gilbert had exhibited in his treatise on the magnet[126] the most perfect specimen of physical research. Leonardo da Vinci had described in the clearest manner the proper method of philosophical investigation;[127] and the whole scientific career of Galileo was one continued example of the most sagacious application of observation and experiment to the discovery of general laws. The names of Paracelsus, Van Helmont, and Cardan have been ranged in opposition to this constellation of great names, and while it is admitted that even they had thrown off the yoke of the schools, and had succeeded in experimental research, their