And because the answer was _not_ precisely what he had looked for, he put the calculation aside, and waited for years. It seems that he mentioned his conjecture to no living person. After many years he took it up again, and worked it out afresh. By this time new measurements of earth’s surface, and new calculations of earth’s size had been made, and Newton had fresh figures to go upon. This time the answer came just as he had originally hoped, and the truth of his surmise was thus proved. Gravity held the moon near the earth, preventing her from wandering off into unknown distances. Gravity held earth and moon, Mars, Venus, Jupiter, each planet, in its own pathway, within a certain distance of the sun. Gravity held many of the comets as permanent members of the Solar System. So strong, indeed, was the drawing of gravity found to be, that only the resisting force of each bright world’s rapid rush round the sun could keep the sun and his planets apart. Newton had discovered the long-sought secret. He had found that “every particle of matter in the universe attracts every other particle?” He had found also the main laws which govern the working of that attraction--that it depends, first, upon the mass or amount of “matter” in each body; that it depends, secondly, upon the distance of one body from another. He found, too, how far attraction increases with greater nearness, and decreases with greater distance. All these and countless other questions he worked out in the course of years. But first he had grasped the great leading principle, after which men had until then groped in vain, that by the force of gravity the sun and his worlds and their moons are all bound together into one large united family or system. Though Newton lived long enough to receive the honor that his astonishing discoveries so justly merited, and though for many years of his life his renown was much greater than that of any of his contemporaries, yet it is not too much to say that, in the years which have since elapsed, Newton’s fame has been ever steadily advancing. We hardly know whether to admire more the sublime discoveries at which he arrived, or the extraordinary character of the intellectual processes by which those discoveries were reached. He died on Monday, March 20, 1727, in the eighty-fifth year of his age. CHAPTER XXXV. LATER ASTRONOMY. Sir William Herschel was born in the city of Hanover, November 15, 1738. He was the second son of Isaac Herschel, a musician, who brought him up, with his four other sons, to his own profession. A faithful chronicler has given us an interesting account of the way in which Isaac Herschel educated his boys; the narrative is taken from the recollections of one who, at the time, was a little girl of five or six years old. She writes: