(The fact itself is known in a variety of different examples. The empire of Asia was, more than once, transferred from the greater to the inferior power. The states of Greece, once so warlike, felt a relaxation of their vigour, and yielded the ascendant they had disputed with the monarchs of the east, to the forces of an obscure principality, become formidable in a few years, and raised to eminence under the conduct of a single man. The Roman empire, which stood alone for ages, which had brought every rival under subjection, and saw no power from whom a competition could be feared, sunk at last before an artless and contemptible enemy. Abandoned to inroad, to pillage, and at last to conquest, on her frontier, she decayed in all her extremities, and shrunk on every side. Her territory was dismembered, and whole provinces gave way, like branches fallen down with age, not violently torn by superior force. The spirit with which Marius had baffled and repelled the attacks of barbarians in a former age, the civil and military force with which the consul and his legions had extended this empire, were now no more. The Roman greatness, doomed to sink as it rose, by slow degrees, was impaired in every encounter. It was reduced to its original dimensions, within the compass of a single city; and depending for its preservation on the fortune of a siege, it was extinguished at a blow; and the brand, which had filled the world with its flames, sunk like a taper in the socket. Such appearances have given rise to a general apprehension, that the progress of societies to what we call the heights of national greatness, is not more natural, than their return to weakness and obscurity is necessary and unavoidable. The images of youth, and of old age, are applied to nations; and communities, like single men, are supposed to have a period of life, and a length of thread, which is spun by the fates in one part uniform and strong, in another weakened and shattered by use; to be cut, when the destined era is come, and to make way for a renewal of the emblem in the case of those who arise in succession. Carthage being so much older than Rome, had felt her decay, says Polybius, so much the sooner; and the survivor too, he foresaw, carried in her bosom the seeds of mortality. The image indeed is apposite, and the history of mankind renders the application familiar. But it must be obvious, that the case of nations, and that of individuals, are very different. The human frame has a general course: it has in every individual a frail contexture and limited duration; it is worn by exercise, and exhausted by a repetition of its functions: but in a society, whose constituent members are renewed in every generation, where the race seems to enjoy perpetual youth, and accumulating advantages, we cannot, by any parity of reason, expect to find imbecilities connected with mere age and length of days.