The Wealth of Nations by Part 1 Chapter 11 Page 213

DIFFERENT EFFECTS OF THE PROGRESS OF IMPROVEMENT UPON THREE DIFFERENT SORTS OF RUDE PRODUCE

These different sorts of rude produce may be divided into three classes. The first comprehends those which it is scarce in the power of human industry to multiply at all. The second, those which it can multiply in proportion to the demand. The third, those in which the efficacy of industry is either limited or uncertain. In the progress of wealth and improvement, the real price of the first may rise to any degree of extravagance, and seems not to be limited by any certain boundary.

That of the second, though it may rise greatly, has, however, a certain boundary beyond which it cannot well pass for any considerable time together. That of the third, though its natural tendency is to rise in the