In the Middle Ages, the merchant was merely one who, as Poppe rightly says, "transferred" the goods produced by guilds or peasants [Poppe, Geschichte der Technologie seit der Wiederherstellung der Wissenschaften bis an das Ende des achtzehnten Jahrhunderts, Band I, Göttingen. 1807, S. 70. — Ed.] The merchant becomes industrialist, or rather, makes craftsmen, particularly the small rural producers, work for him. Conversely, the producer becomes merchant. The master weaver, for instance, buys his wool or yarn himself and sells his cloth to the merchant, instead of receiving his wool from the merchant piecemeal and working for him together with his journeymen. The elements of production pass into the production process as commodities bought by himself. And instead of producing for some individual merchant, or for specified customers, he produces for the world of trade. The producer is himself a merchant. Merchant's capital does no more than carry on the process of circulation. Originally, commerce was the precondition for the transformation of the crafts, the rural domestic industries, and feudal agriculture, into capitalist enterprises. It develops the product into a commodity, partly by creating a market for it, and partly by introducing new commodity equivalents and supplying production with new raw and auxiliary materials, thereby opening new branches of production based from the first upon commerce, both as concerns production for the home and world-market, and as concerns conditions of production originating in the world-market. As soon as manufacture gains sufficient strength, and particularly large-scale industry, it creates in its turn a market for itself, by capturing it through its commodities. At this point commerce becomes the servant of industrial production, for which continued expansion of the market becomes a vital necessity. Ever more extended mass production floods the existing market and thereby works continually for a still greater expansion of this market for breaking out of its limits. What restricts this mass production is not commerce (in so far as it expresses the existing demand), but the magnitude of employed capital and the level of development of the productivity of labour. The industrial capitalist always has the world-market before him, compares, and must constantly compare, his own cost-prices with the market-prices at home, and throughout the world. In the earlier period such comparison fell almost entirely to the merchants, and thus secured the predominance of merchant's capital over industrial capital.