12 
ON THE NATURE 
as to one and not as to the other; to suppose 
that the value of a to B could be altered, and 
not the value of B to A, would, as I have al- 
ready remarked, be as absurd, as supposing 
that the distance of the sun from the earth 
could be increased or decreased, while the dis- 
tance of the earth from the sun remained as 
hYefore. 
The truth intended to be conveyed by saying 
that B remains of the same value is, that the 
cause of the altered relation between A and B 
is in the former, and not in the latter; and to 
determine where the change originated is in 
fact the whole object of those who endeavour 
to show what commodities have remained 
stationary in value, and what have varied. 
It is so important to bear in mind, in these 
cases of rising and falling, that as A rises, B 
necessarily falls; or, to speak with greater pre- 
cision, that the value of A cannot increase in 
relation to B, without the value of B decreasing 
in relation to aA, that I may be pardoned for 
still further showing the impropriety, or at least 
the danger, of using the terms rise and fall in