OF VALUE.

105

cumstances which make no difference in the
power of expressing the value of a and c in B,
and certainly no difference in the power of
comparing the value of 4 and ¢ when expressed.

This supposition, of the necessity of invariable
 value in any commodity employed as a
measure, proceeds, as I have already remarked,
on a false analogy. Because a measure of
space must be invariable in its length, a measure
 of value, it has been argued, must be invariable
 in its value*. To expose the fallacy
of this inference, let us examine in the first
place, what are the character and circumstances
of that invariableness which is requisite for a
measure of length, All that is required ap-*

 ¢ Asa measure of quantity,” says Adam Smith,
‘¢ guch as the natural foot, fathom, or handful, which is
continually varying in its own quantity, can never be an
accurate measure of the quantity of other things; so a
commodity, which is itself continually varying in its own
value, ean never be an accurate measure of the value of
other commodities.” Wealth of Nations, Book i, Chap. 5.