Equal quantities of labour will, at distant times, be purchased more nearly with equal quantities of corn, the subsistence of the labourer, than with equal quantities of gold and silver, or, perhaps, of any other commodity. Equal quantities of corn, therefore, will, at distant times, be more nearly of the same real value, or enable the possessor to purchase or command more nearly the same quantity of the labour of other people. They will do this, I say, more nearly than equal quantities of almost any other commodity; for even equal quantities of corn will not do it exactly. The subsistence of the labourer, or the real price of labour, as I shall endeavour to shew hereafter, is very different upon different occasions; more liberal in a society advancing to opulence, than in one that is standing still, and in one that is standing still, than in one that is going backwards. Every other commodity, however, will, at any particular time, purchase a greater or smaller quantity of labour, in proportion to the quantity of subsistence which it can purchase at that time. A rent, therefore, reserved in corn, is liable only to the variations in the quantity of labour which a certain quantity of corn can purchase. But a rent reserved in any other commodity is liable, not only to the variations in the quantity of labour which any particular quantity of corn can purchase, but to the variations in the quantity of corn which can be purchased by any particular quantity of that commodity.