The importance of a good road, protected by military posts at short intervals, in securing the tranquillity of a turbulent district, is strikingly shewn in another instance. That part of the great highway between Madrid and Cadiz which crosses the wild hills of the Sierra barrier, was formerly left to the robber and the wolf, without roads or villages. A road, admirably planned, was at length executed by Charles Le Maur, an able engineer in the service of Charles III. The task of guarding it was the difficulty next to be overcome. For this purpose, Spain, who had colonized the new world, and expelled her rich Jews and industrious Moors, was compelled to resort to foreign assistance. In 1768, a colony of Germans and Swiss settled upon the line on condition of maintaining a constant guard.[36] This is done to the present day. Several consecutive towns, such as Carolina, in Andalusia, are occupied by people speaking nothing but the German language, and regular patrols are constantly on the move from one town to another. These Germans have their land in better order and cultivation than the Spaniards. This Spanish highway, with its stations at regular intervals, with its foreign guards, who from generation to generation maintain the tongue and the habits of their fatherland, presents too many points of resemblance to the manner in which the northern frontier of Roman power in Britain was defended, to be passed over without obtaining at least this brief notice. [Sidenote: MILITARY ROADS.]