LAND AND LABOUR 199 



make any comparison ; and we must admit that the Book in 



parts played by land and labour in producing them 



are "indefinite and incommensurable," precisely as 



Mill says they are. But the two, the five, or the 



ten extra loaves which result when labour is applied 



to the second, the third, and the fourth acre 



respectively, but do not result at all so long as it is 



applied only to the first, constitute phenomena of a 



different order altogether. The labour being in 



each of the four cases the same, and these additional 



loaves resulting in three cases only, these additional 



loaves are obviously not due to labour, but to certain 



additional qualities present in the last three acres 



and not present in the first. In other words, though The extra pro 



i 11 Tv/r-ii ,T duct resulting 



in producing the loaves, or, as Mill puts it, "the from labour 

 effect" the parts played respectively by land and 

 labour are incommensurable so long as the land, 

 the labour, and the effect remain the same, the parts 

 become immediately mensurable as soon as the 

 effect begins to vary, and one of the causes, and one 

 of the causes only, varies also. 



This truth can be yet further elucidated by This is easily 



r T\/TMI> i ' -11 rr i provedbya 



means ot Mills two other illustrations. If the two number of 

 blades of a pair of scissors were made of two niustrations. 

 different materials, and the one blade were of such 

 a nature that it was always of the same quality, and 

 human ingenuity was not capable of improving it, 

 whilst the qualities of the other blade varied with 

 the skill devoted to its manufacture, and if one pair 

 of scissors should cut twenty yards of cloth in a 

 minute, whilst another cut only ten, the additional 



to 



not 



