The improvement in the productive powers of useful labour depends, first, upon the improvement in the ability of the workman; and, secondly, upon that of the machinery with which he works. But the labour of artificers and manufacturers, as it is capable of being more subdivided, and the labour of each workman reduced to a greater simplicity of operation, than that of farmers and country labourers; so it is likewise capable of both these sorts of improvement in a much higher degree {See book i chap. 1.} In this respect, therefore, the class of cultivators can have no sort of advantage over that of artificers and manufacturers.