That men of science and philosophers should have approved Newton's theory is not surprising, but it is somewhat curious that it excited so little opposition among theologians. Galileo's discoveries of hills, vales, and (supposed) seas on the moon and planets had already suggested that life might exist there, and in the popular (but illogical) view this involved the idea of the existence of beings with spiritual and intellectual faculties not unlike those of men. Newton's results seemed to show that there was nothing in the nature of things to differentiate the earth from the other planets, and therefore considerably strengthened the view that life might be found on them. It might well be asked whether such life, and indeed whether the mechanism of the solar system as expounded by Newton, was in accordance with Scripture. That these difficulties were not pressed against Newton's conclusions is, I think, attributable to the fact that his theory was explicitly concerned only with non-organic matter. His own opinion was that the extension of the reign of law was an additional argument in favour of a divine creation: this view, set out at the end of the _Principia_ and in his five letters to Bentley in 1692-93, was generally accepted by the leaders of religious thought in Britain. Lagrange more than once remarked that Newton was not only the greatest mathematician of former days, but the most fortunate, since, as there is but one universe, it can happen to but one man in the world's history to be the interpreter of its laws. It is true that Newton applied his theory only to the solar system for which alone he had the necessary data, but after the publication of the _Principia_, no one doubted that gravity extended to the most distant regions of space. The work of Sir William Herschel and that of all later astronomers on binary and other systems rests on this hypothesis. The influence of the _Principia_ on dynamical astronomy has been permanent. It is not too much to say that when it was published, the theory, as there set out, had outstripped observation, but during the succeeding century large numbers of new facts were collected, and applications of the theory to new problems were made, notably by Clairaut, Euler, and Lagrange. All these researches tended to confirm it. The demonstrations in the _Principia_ are expressed in the language of classical geometry, and, though unnecessarily concise and difficult, their correctness is unimpeachable. That Newton could carry his calculations so far with the limited mathematics then at his command is not the least wonderful part of the performance, but it is the prerogative of genius to get great results with but scanty equipment.