With fixed residence the forms of communities alter. The group settles in a certain district, homes are built close to one another, and the patriarchal organisation gives place to the village, which, with its definite boundaries, is thenceforth the nucleus of the social aggregate. Often several village communities have fields and forests in common, and a common ownership of dams and canals; Nature takes care that they do not become isolated, but unite together in close contact for common defence and protection. With agriculture is associated the working up of raw products. These are fashioned into materials for the support of life and for enjoyment; furniture for dwellings, clothing, tools, utensils, and weapons are made. For, however much agriculture favours a life of peace, so rarely does man live in friendship with his fellows that agricultural peoples also find it necessary to arm themselves for war. At first manufacture is not separated from farming; the agriculturist himself prepares the natural products, assisted by the members of his family. Later, it is easily seen that some individuals are more skilled than others; it is also recognised that skill may be developed by practice and that employments must be learned. Therefore it is requisite that special individuals of the community should prepare themselves for particular activities in the working up of raw products and pursue these activities in consistency with the needs of the society--trade or craft. The craftsman at first labours for the community; in every village the tailor, cobbler, smith, barber, and schoolmaster is supported by society at large. The craftsman receives his appointed income--that is, his portion of the common supply of food; and, in addition, every one for whom he expends his labour gives him something in compensation, or finds him food while employed about his house, until, finally, a systematic method of exchange is established; and with this another advance--an epoch for civilisation--is arrived at. [Sidenote: The First Labour Problem]