The injunction given to man to "replenish the earth and subdue it" could not possibly be fulfilled with implements of stone. To fell a tree with a flint hatchet would occupy the labour of a month, and to clear a small patch of ground for purposes of culture would require the combined efforts of a tribe. For the same reason, dwellings could not be erected; and without dwellings domestic tranquillity, security, culture, and refinement, especially in a rude climate, were all but impossible. Mr. Emerson well observes, that "the effect of a house is immense on human tranquillity, power, and refinement. A man in a cave or a camp--a nomad--dies with no more estate than the wolf or the horse leaves. But so simple a labour as a house being achieved, his chief enemies are kept at bay. He is safe from the teeth of wild animals, from frost, sunstroke, and weather; and fine faculties begin to yield their fine harvest. Inventions and arts are born, manners, and social beauty and delight." But to build a house which should serve for shelter, for safety, and for comfort--in a word, as a home for the family, which is the nucleus of society--better tools than those of stone were absolutely indispensable. Hence most of the early European tribes were nomadic: first hunters, wandering about from place to place like the American Indians, after the game; then shepherds, following the herds of animals which they had learnt to tame, from one grazing-ground to another, living upon their milk and flesh, and clothing themselves in their skins held together by leathern thongs. It was only when implements of metal had been invented that it was possible to practise the art of agriculture with any considerable success. Then tribes would cease from their wanderings, and begin to form settlements, homesteads, villages, and towns. An old Scandinavian legend thus curiously illustrates this last period:--There was a giantess whose daughter one day saw a husbandman ploughing in the field. She ran and picked him up with her finger and thumb, put him and his plough and oxen into her apron, and carried them to her mother, saying, "Mother, what sort of beetle is this that I have found wriggling in the sand?" But the mother said, "Put it away, my child; we must begone out of this land, for these people will dwell in it."