AT DIFFERENT PERIODS. 93 
while the comparative quantities of labour re- 
mained the same. 
Again, an alteration in the positive quantities 
of the producing labour in a and B, which left 
the comparative quantities the same, would not 
affect the mutual value of these two commodi- 
ties, any more than an alteration in the positive 
values of the producing labour, while the same 
ratio subsisted between those values as before.