Though the real value of a corn rent, it is to be observed, however, varies much less from century to century than that of a money rent, it varies much more from year to year. The money price of labour, as I shall endeavour to shew hereafter, does not fluctuate from year to year with the money price of corn, but seems to be everywhere accommodated, not to the temporary or occasional, but to the average or ordinary price of that necessary of life. The average or ordinary price of corn, again is regulated, as I shall likewise endeavour to shew hereafter, by the value of silver, by the richness or barrenness of the mines which supply the market with that metal, or by the quantity of labour which must be employed, and consequently of corn which must be consumed, in order to bring any particular quantity of silver from the mine to the market. But the value of silver, though it sometimes varies greatly from century to century, seldom varies much from year to year, but frequently continues the same, or very nearly the same, for half a century or a century together. The ordinary or average money price of corn, therefore, may, during so long a period, continue the same, or very nearly the same, too, and along with it the money price of labour, provided, at least, the society continues, in other respects, in the same, or nearly in the same, condition. In the mean time, the temporary and occasional price of corn may frequently be double one year of what it had been the year before, or fluctuate, for example, from five-and-twenty to fifty shillings the quarter. But when corn is at the latter price, not only the nominal, but the real value of a corn rent, will be double of what it is when at the former, or will command double the quantity either of labour, or of the greater part of other commodities; the money price of labour, and along with it that of most other things, continuing the same during all these fluctuations.