The Roman empire in ancient times afforded the clearest demonstration of the truth of these principles; and the fate of their vast dominion shows, in the most decisive manner, what is the inevitable consequence to which the free trade principles, now so strongly contended for by a party in this country, must lead. Alison is the first modern author with whom we are acquainted, who has traced the decline of the Roman empire in great part to this source. In the tenth volume of his "History of Europe," p. 752, we find the following passage:-- "No nation can pretend to independence which rests for any sensible protion of its subsistence in ordinary seasons on foreign, who may become hostile, nations. And if we would see a memorable example of the manner in which the greatest and most powerful nation may, in the course of ages, come to be paralysed by this cause, we have only to cast our eyes on imperial Rome, when the vast extent of the empire had practically established a free trade in grain with the whole civilized world; and the result was, that cultivation disappeared from the Italian plains, that the race of Roman agriculturists, the strength of the empire, became extinct, that the fields were laboured only by slaves and cattle. The legions could no longer be recruited but from foreign bands, vast tracts of pasturage overspread even the fields of Lombardy and the Compagna of Naples, and it was the plaintive confession of the Roman annalist, that the mistress of the world had come to depend for her subsistence on the floods of the Nile." This observation has excited, as well it might, the vehement indignation of the free trade journals. The example of the greates and most powerful nation that ever existed being weakened, and at length ruined by a free trade in corn, afforded too cogent an argument, and was too striking a warning, not to excite the wrath of those who would precipitate Great Britain into a similar course of policy. They have attacked the author, accordingly, with unwonted asperity; and, while they admint the ruin of Italian agriculture in the later stages of the Roman empire, endeavour to ascribe it to the gratuitous distribution of grain to the Roman populace, not the effect of a free importation of grain from its Egyptian and African provinces. The vast importance of the subject has induced us to look into the original authorities to whom Alison refers in support of his observation, and from among them we select three--Tacitus, Gibbon, and Michelet. Tacitus says, "At Hercule _olim ex Itaila_ legionibus longinquas in provincias commeatus portabantur, _nec nunc infecunditate laboratur_; sed Africam _potius et Egyptum exercemus_, navibusque et casibus vita populi Romani permissa est."--TACITUS, _Annal_. xii. 43.