90 ON COMPARING COMMODITIES 
the labour in B; and again in 1811, 40s. is to 
20s., the values of the commodities, as 36s. to 
18s., the values of the labour. 
The author appears to me to have vacillated 
unconsciously between two essentially distinct 
propositions. He has begun (not an uncom- 
mon case) by proposing one as the object of 
his attack, and ended by contending with the 
other. 
This will be seen at a glance when they are 
placed together. 
1. A and B are to each other in value as the 
values of the producing labour. 
2. The value of aA at one period is to the 
value of the producing labour, as the value of 
a at another period is to the value of the pro- 
ducing labour; or, to conform the expression 
of it to the preceding instance, the value of a 
in 1810, 40s., is to the value of the labour at 
that period, 24s., as the value of aA in 1811, 
40s., to the value of the producing labour in 
the same year, 36s., which is manifestly ab-