It is probable that Lake dwellings were also used in Asia and in Africa from prehistoric times. History tells us that the inhabitants of Phasis, the Mingrelians of the present day, lived in reed huts on the water, and that they went from one islet to another in canoes hollowed out of the trunks of oak-trees. A bas-relief from the palace of Sennacherib, preserved in the British Museum, represents warriors fighting on artificial islands made of large reeds. But here w e enter the domain of history, and we must return to Neolithic times, and speak of the habitations built of more durable materials and the ruins of which are still standing. It is impossible to say with any certainty to what period the most ancient of these structures belong. It is probable that man early learned to pile up stones, binding them together at first with clay, and then with some stronger cements. The _burghs_ of Scotland, the _nurhags_ of the island of Sardinia, the _talayoti_ of the Balearic Isles, the _castellieri_ of Istria, are all ancient witnesses of the modes of building employed in the most remote ages. _Burghs, brocks_, or _broughs_ are numerous in Scotland,23 and also in the islands of the Atlantic. For a long time they were supposed to be of Scandinavian origin, but Sir J. Lubbock24 remarks With reason that no building at all like them exists in Norway or in Denmark, and it is difficult to admit the idea that the Scandinavians set up in the islands tributary to them buildings which were unknown to their own mainland. We are therefore disposed to think that these curious structures, which were inhabited until the twelfth and thirteenth centuries of the Christian era, are of much earlier date than the first invasion by the Northmen, and that the burgh still standing on the little island of Moussa, one of the Shetlands, is one of the best examples that we can quote. A tower, forty-one feet high, rises on the borders of the sea. The walls are of unhewn stones, piled up without cement, and they form two circles, separated by a passage four feet wide. In each story are a series of very small openings, intended to admit air and light to the cell-like rooms inside, and to a staircase that leads to the top of the tower. The only way into this burgh is through a door only seven feet high, and so narrow that it is impossible for two people to go in abreast.