The Wealth of Nations by Part 5 Chapter 2 Page 269

Tobacco being a luxury, every man is allowed to buy or not to buy as he chooses. But salt being a necessary, every man is obliged to buy of the farmer a certain quantity of it; because, if he did not buy this quantity of the farmer, he would, it is presumed, buy it of some smuggler. The taxes upon both commodities are exorbitant. The temptation to smuggle consequently is to many people irresistible, while at the same time the rigour of the law, and the vigilance of the farmer’s officers, render the yielding to that temptation almost certainly ruinous. The smuggling of salt and tobacco sends every year several hundred people to the galleys, besides a very considerable number whom it sends to the gibbet. Those taxes levied in this manner yield a very considerable revenue to government.

In 1767, the farm of tobacco