This open and admitted fact is the foundation of the whole argument of the Duke of Wellington. In the evening of a glorious life, the greater part of which has been spent in the active service of his country, the veteran soldier has thought it his duty to remind us, for our own guidance and that of our children, of the actual existing state of our national defences, which he deems to be insufficient. It is one of the last, but not, we think, the least important of the services which the venerable Duke has rendered to the nation, with whose proudest history his name will be eternally associated. We take it--or at least we ought to take it--from his lips, as a solemn warning; as the disinterested testimony of a man alike pre-eminent in war and in council; as the deliberate opinion of the GREAT PACIFICATOR OF EUROPE. For notwithstanding the irreverent, mean, and scurrilous taunts of the Manchester gang of demagogues, it is undeniable that the Great Duke has been the chief instrument in procuring for us the blessing of that peace which for two and thirty years we have enjoyed. It was his conquest at Waterloo which hushed the world. The tranquillity of Europe was the stake for which he fought, and he nobly won it. And now, when, at the last hour, this illustrious man comes forward to offer us his advice, and to warn us against the folly of trusting too implicitly to the continuance of that tranquillity, is it wise that we should scorn his counsel? And what is the proposal which has excited such wrath, and so sorely roused the choler of the bilious Cobden? Simply this--that the British nation should at all times maintain at home a military force sufficient to repel an invasion, should such be attempted, from our shores. The Duke believes and maintains that we cannot now, as formerly, rely solely and implicitly upon our navy for defence, but that, in the event of a war, we must provide against the contingency of an enemy's landing. Our arsenals, he thinks, and our dockyards, should be supported by a military force, and at least we ought to exhibit such a front as will hold out no temptation to a hostile attempt. These are not aggressive, but precautionary measures; and without them, according to the Duke, we cannot consider ourselves secure. Such are the proposals which Cobden and his clique--we are sorry to observe a gentleman like Sir William Molesworth among them--are prepared to resist to the last. They want no defences at all. They are opposed to any augmentation of the army. They would rather do without it, or reduce the establishment so as to make the national saving equivalent to the diminished amount of revenue consequent upon their commercial experiments. They look upon free-trade as a universal panacea which is to cure all national and social ailments, and to remedy every grievance. War is to be no more--territorial aggressions unknown--and the advent of the millennium is to be typified by an unbounded exportation of calico!