In 1712 the export trade of England is officially estimated at £6,644,103,[4] or considerably less than one-sixth of the home trade of that date as calculated by Smith in his _Memoirs of Wool_. Such an estimate, however, gives an exaggerated impression of the relation of foreign to home trade, because under the latter no account is taken of the large domestic production of goods and services which figure in no statistics. A more instructive estimate is that which values the total consumption of the English people in 1713 at forty-nine or fifty millions, out of which about four millions covers the consumption of foreign goods.[5] In 1740 imports amounted to £6,703,778, exports to £8,197,788. In 1750 they had risen respectively to £7,772,339 and £12,699,081,[6] and ten years later to £9,832,802 and £14,694,970. Macpherson, whose _Annals of Commerce_ are a mine of wealth upon the history of foreign commerce in the eighteenth century, after commenting upon the impossibility of obtaining a just estimate of the value of home trade, alludes to a calculation which places it at thirty-two times the size of the export trade. Macpherson contents himself with concluding that it is "a vast deal greater in value than the whole of the foreign trade."[7] There is every reason to believe that in the case of Holland and France, the only two other European nations with a considerable foreign trade, the same general conclusion will apply. [Illustration: PROGRESS OF FOREIGN TRADE IN ENGLAND.] The smallness of the part which foreign trade played in industry signifies that in the earlier part of the eighteenth century the industrial organism as a whole must be regarded as a number of tolerably self-sufficing and therefore homogeneous national forms attached to one another by bonds which are few and feeble. As yet there was little specialisation in national industry, and therefore little integration of national parts of the world-industry. § 2. Since the breaking-down of international barriers and the strengthening of the industrial bonds of attachment between nations will be seen to be one of the most important effects of the development of machine-industry, some statement of the nature of these barriers and their effect upon the size and character of international trade is required.