Herein it might appear that Adam Smith had novelty to contribute; yet nothing is more certain than that his full sense of the world as the only true unit of marketing was fully grasped before him. In 1691 Sir Dudley North published his _Discourses upon Trade_. Therein he clearly sees that commercial barriers between Great Britain and France are basically as senseless as would be commercial barriers between Yorkshire and Middlesex. Indeed, in one sense, North goes even further than Adam Smith, for he argues against the usury laws in terms Bentham would hardly have disowned. Ten years later an anonymous writer in a tract entitled _Considerations on the East India Trade_ (1701) has no illusions about the evil of monopoly. He sees with striking clarity that the real problem is not at any cost to maintain the industries a nation actually possesses, but to have the national capital applied in the most efficient channels. So, too, Hume dismissed the Mercantile theory with the contemptuous remark that it was trying to keep water beyond its proper level. Tucker, as has been pointed out, was a free trader, and his opinion of the American war was that it was as mad as those who fought "under the peaceful Cross to recover the Holy Land"; and he urged, indeed, prophesied, the union with Ireland in the interest of commercial amity. Nor must the emphasis of the Physiocrats upon free trade be forgotten. There is no evidence now that Adam Smith owed this perception to his acquaintance with Quesnay and Turgot; but they may well have confirmed him in it, and they show that the older philosophy was attacked on every side.