In the employment of labour and machinery, it is often found that the effects can be increased by skilful distribution, by separating all those operations which have any tendency to impede one another, and by bringing together all those operations which can be made in any way to aid one another. As men in general cannot perform many different operations with the same quickness and dexterity with which they can by practice learn to perform a few, it is always an advantage to limit as much as possible the number of operations imposed upon each. For dividing labour, and distributing the powers of men and machinery, to the greatest advantage, it is in most cases necessary to operate upon a large scale; in other words, to produce the commodities in greater masses. It is this advantage which gives existence to the great manufactories; a few of which, placed in the most convenient situations, frequently supply not one country, but many countries, with as much as they desire of the commodity produced.
James Mill