The above wonderful discovery of elliptic orbits, in place of circular orbits, was only one among many made by the illustrious Kepler--discoveries not carelessly hit upon, as one might pick up in the street a valuable stone which somebody had dropped, but earnestly sought for, and found with toil and diligence, as gems are first found in foreign lands, after much seeking and long patience. Casual discoveries in science are rare. Attainment is far more usually made through intense study, through hard work, through profound thought, through a gradual groping upward out of darkness to the point where daylight breaks forth. The three well-known “Laws of Kepler” still lie at the very foundation of the modern system of astronomy. They are: First, every planet moves in an elliptical orbit, in one focus of which the sun is situated; second, the line drawn from the sun to a planet moves over equal areas in equal times; and, third, the square of the periodic times of the planets varies inversely as the cubes of their distances. CHAPTER XXXIII. MODERN ASTRONOMY. Still, however, the world was not convinced of the truth of the Copernican system. One man here or there saw and acknowledged its reality. The mass of mankind continued firmly to believe that they dwelt at the universe center, and utterly to scout the idea of a moving earth. Indeed, it may be very much doubted whether, not merely the mass of mankind, but even the most civilized and cultivated portion of that mass, had as yet, to any wide extent, heard a whisper of the new theories. Knowledge, in those days, traveled from place to place with exceeding deliberation. Another great man arose, contemporary with Kepler--a man whose story seizes more strongly upon our imagination than that of the severe and successful studies of Kepler. From an ordinary worldly point of view, Kepler would hardly be looked upon as altogether a successful man. He was poor, and in sickly health. His chief book was promptly prohibited by Rome--then a power in the whole reading world of Europe to an extent which can hardly be realized in these days of freedom. Kepler’s book was placed in the forbidden category, side by side with the dying publication of Copernicus. This checked all hope of literary gains, and life with Kepler was one long struggle. But if he could have looked ahead two or three hundred years; if he could have foreseen the time when not a few wise men of science alone, but all the civilized world, including the very Church which condemned him, should meekly have accepted and indorsed his discoveries,--then he would have been able to gauge the measure of his own real success. Moreover, with all his troubles, Kepler was so happy as to escape absolute persecution. He lived in a country which knew something of liberty as an ideal; he was left to write and work freely; and, at least, no public recantation of what he held to be truth was forced from him.