We come now to another method for increasing the relative amount of the surplus-value, the manufactory proper, a more developed form of coöperation, which became general between the middle of the sixteenth century and the end of the eighteenth. This comes from two causes. On the one side it is due to the combination of different trades, up to that point independent of each other. The manufacture of a carriage, for example, requires the work of a wheelwright, a harness-maker, a painter, etc., who all exercise their trades independently of each other. The capitalist unites them all in one trade, that of carriage-maker, in which the occupation of each becomes more limited, more specialized. The painter, for example, becomes especially a painter of carriages. On the other side the manufactory is due to the bringing together of workmen of the same trade into a single workshop, and to the division of labor made possible in this way. Thus, for instance, in the manufacture of pins, each pin is no longer made by a single workman but by several, each of whom does only a special part of the work. It is clear that through the introduction of manufactory methods the productivity of labor has been enormously increased, so that the time necessary for the production of the necessaries of life for the workmen has become shorter, and the surplus-value correspondingly augmented. The part taken by the workman in the process of production is quite different from what it was in the time of the guilds. The different operations that he performed in making the complete product are now replaced by the monotonous and repeated production of a single one of the parts. From this point dates the division of workmen into skilled and unskilled laborers. The latter are those whose work is such as to require little or no apprenticeship, and they are the cause of a new lowering of the price of labor. We have still to take up the question of the introduction of machinery and of manufacturing on a large scale. Although at the period of the early manufactories the workman was obliged to perform a monotonous task, which in so far may be called “mechanical”, yet this task was performed, though with the aid of tools, by his own hands. But in the eighteenth century the machine was invented, that is to say, a mechanism which took the place both of the workman and of his tools. Machines were introduced because they saved hand-work, and consequently lowered the price of the product and relatively increased the surplus-value.