The Wealth of Nations by Part 4 Chapter 8 Page 4

the custom house. The private interest of our merchants and manufacturers may, perhaps, have extorted from the legislature these exemptions as well as the greater part of our other commercial regulations.

They are, however, perfectly just and reasonable, and if, consistently with the necessities of the state, they could be extended to all the other materials of manufacture, the public would certainly be a gainer.

The avidity of our great manufacturers, however, has in some cases extended these exemptions a good deal beyond what can justly be considered as the rude materials of their work. By the 24th George III, c. 46, a small duty of only one penny the pound was imposed upon the importation of foreign brown linen yam, instead of much higher duties to which it had been subjected before,