The Wealth of Nations by Part 4 Chapter 4 Page 6

But upon such exportation, no part of these duties are drawn back. Our manufacturers are unwilling, it seems, that even this restricted importation should be encouraged, and are afraid lest some part of these goods should be stolen out of the warehouse, and thus come into competition with their own. It is under these regulations only that we can import wrought silks, French cambrics and lawns, calicoes painted, printed, stained or dyed, etc.

We are unwilling even to be the carriers of French goods, and choose rather to forego a profit to ourselves than to suffer those, whom we consider as our enemies, to make any profit by our means. Not only half the Old Subsidy, but the second twenty-five per cent, is retained upon the exportation of all French goods.

By the fourth of the rules annexed