INTRODUCTION.

11

The other two things, exchange and price, are neither of
them, in any sense, natural facts or ideal facts. If two
men exchange their possessions it becomes a fact that they
nave made the exchange. Each of them might, quite
correctly, consider that which he gave, as the price of
that which he received, and in that sense, it would
vecome a fact that each of them had paid a price. But
what natural fact is involved in the transaction? The
axchange may have been a good hat for an old pair of
soots. Under some other conditions or relations the
one item might have been worth twice or four times as
much as the other, but, actually, the one party who had
‘he boots wanted the hat, and wice versa ; and so they
xchanged.
But, it may be said, there must be some intelligible
sense or meaning in which Prof. Cairnes uses the expression
 ‘natural fact” It may be so: the next sentence
is evidently intended as in some degree explanatory :
“These are the phenomena of wealth, and the natural
aws of these phenomena are certain constant relations
mn which they stand towards each other and towards
‘heir causes. For example, capital grows from year to
gear in this country at a certain rate of progress; in the
United States the rate is considerably more rapid; in
China considerably slower.” Here we find the example
lirectly contradicting the proposition to which it is
appended as an illustration. Instead of the relation
being constant, the example exhibits the relation
18 inconstant; in neither two out of the three instances,
's the relation shown to be constant. The specific
gravity of water is the same in China as in Eng-