When the same philosopher directed his telescope to the fixed stars, if he was disap• pointed at finding their magnitudes not increased, he was astonished and delighted to find them multiplied in so great a degree, and such numbers brought into view, which were invisible to the naked eye. In Jupiter he perceived a large disk, approaching in size to the moon. Near it,. as he saw it for the first time, were three luminous points ranged in a straight line, two of them on one side of the planet, and one on the other. This occasioned no surprise, for they might be small stars not visible to the naked eye, such as he had already discovered in great numbers. By observing them, however, night after night, he found these small stars to be four in number, and to be moons or satellites, accompanying Jupiter, and revolving round him, as the moon revolves round the earth.
The eclipses of these satellites, their conjunctions with the planet, their disappearance behind his disk, their periodical revolutions, and the very problem of distinguishing them from one another, offered, to an astronomer,' a series of new and interesting observations.
In Saturn he saw one large disk, with two smaller ones very near it, and diametrically opposite, and always seen in the same places ; but more powerful telescopes were required Before these appearances could be interpreted.
The horned figure of Venus, and the gibbosity of Mars, added to the evidence of the Copernican system, and verified the conjectures of its author, who had ventured to say, that, if the sense of sight were sufficiently powerful, we should see Mercury and Venus exhibiting phases similar to those of the moon.
The spots of the sun derived an interest from their contrast with the luminous disk over which they seemed to pass. They were found to have such regular periods of re turn, as could be derived only from the motion of the disk itself ; land thus the sun's revo lution on his axis, and the time of that revolution, were clearly ascertained.
This succession of noble discoveries, the most splendid, probably, which it ever fell to the lot of one individual to make, in a better age would have entitled its author to the admiration and gratitude of the whole scientific world; but was now viewed from several quarters with suspicion and jealousy. The ability and success with which Galileo had laboured to overturn the doctrines of Aristotle and the schoolmen, as well as to establish the motion of the earth, and the immobility of the sun, had excited many enemies. There are always great numbers who, from habit, indolence, or fear, are the determined support ers of what is established, whether in practice or in opinion. To these the constitution of the universities of Europe, so entirely subjected to the church, had added a numerous and learned phalinx, interested to preserve the old systems, and to resist all innovations. which could endanger their authority or their repose. The church itself was roused to action, by reflecting that it had staked the infallibility of its judgments on the truth pf the very opinions which were now in danger of being overthrown. Thus was formed a vast combi
nation of men, not very scrupulous about the means which they used to annoy their adver saries ; the power was entirely in their hands, and there was nothing but truth and rea son to be opposed to it.
The system of Copernicus, however, while it remained obscure, and known only to as tronomers; created no alarm in the church. It had even been ushered into the world at the solicitation of a cardinal, and under the patronage of the Pope ; but when it became more popular, when the ability and acuteness of Galileo were enlisted on its side, the , consequences became alarming ; and it was determined to silence by force an adversary who could not be put down by argument. His dialogues contained a full exposition- of the evidence of the earth's motion, and set forth the errors of the old, as well as the dis coveries of the new philosophy, with great force of reasoning, and with the charms of the most lively eloquence. They are written, indeed, with such singular felicity, that one reads them at the present day, when the truths contained in them are known and admit ted, with all the delight of novelty, and feels one's self carried back to the period when _ the telescope was first directed to the heavens, and when the earth's motion, with all its train of consequences, was proved for the first timed The author of such a work could not be forgiven. Galileo, accordingly, was twice brought before the Inquisition. The first time a council of seven cardinals pronounced a sentence which, for the sake of those disposed to believe that power can subdue truth, ought never to be forgotten : That to maintain the sun to be immoveable, and without local motion, in the centre of the world, is an absurd proposition, false in philosophy, heretical in religion, and contrary to the tes timony of Scripture. That it is equally absurd and false in philosophy to assert that the earth is not immoveable in the centre of the world, and, considered theologically, equally , erroneous and heretical." These seven theologians might think themselves officially entitled to decide on what was heretical or orthodox in faith, but that they should determine what was true or false in philosophy, was an insolent invasion of a territory into which they had no right to en ter, and is a proof how ready men are to suppose themselves wise, merely becaUse they happen to be powerful. At this time a promise was extorted from Galileo, that he would not teach the doctrine of the earth's motion, either by speaking or by writing. To this promise he did not conform. His third dialogue, published, though not till long after wards, contained such a full display of the beauty and simplicity of the new system, and such an exposure of the inconsistencies of Ptolemy and Tycho, as completed the triumph of Copernicus.