But however much we may take from the moral greatness usually attributed to Newton—and a considerable abatement is unquestionably necessary—his reputation for wonderful sagacity and grasp of mind is incapable of impeachment. The course of events has only served to render more conspicuous that sublime intelligence by which he unraveled the mechanism of the heavens, and establish more indisputably his claim to be regarded as the architect of physical astronomy. To determine the motions of the heavenly bodies was the work of Keppler: to explain and demonstrate the causes of those motions was the achievement of Newton. So far, however, from gaining universal assent when first proposed, his theory was ill understood, slightly appreciated, or altogether rejected by numbers of scientific men; and—especially on the continent—it very slowly won its way to notice and confidence. Newton survived the publication of the Principia forty years, and at the time of his death—according to Voltaire—it had not twenty readers out of the country of its production. It was not until the mutual perturbations of the planets began to occupy the attention of the continental philosophers, that his theory was fully admitted abroad, and the work in which it was developed took the rank it has since occupied, preëminent—in the words of Laplace—above all the productions of the human mind. It is a common, but vulgar error, to suppose the merit of our countryman to lie in conceiving the idea of the attraction of gravitation. That idea had been suggested to many minds long before his time, and the impression had been created that such a power in nature was the cause of the planetary motions. Thus Keppler surmised an attractive force to reside in the sun, producing these movements; and he even threw out the conjecture that this force diminishes in proportion to the square of the distance of the body on which it was exerted. Borelli and Hooke, also, distinctly developed the influence of gravity; and both referred the orbits of the planets to the doctrine of attraction combining with their own proper motions to produce curvilinear movements. What really distinguished Newton, was not the idea of gravity as the principle of attachment between the different members of the solar system, but proving it to be so. He succeeded vague surmise upon the point with mathematical demonstration: explained and applied the laws of the force—an accomplishment which crowns him with honor above all his rivals; inasmuch as he who works a mine, and distributes its wealth through society, is incomparably in advance of him who has merely apprehended its existence, but failed in gaining access to its treasures. [Illustration]