That this boundary is not an isolated phenomenon is well seen by comparing it with the boundary between the France which reintroduced the Roman law (_Droit Écrit_) early in the Middle Ages and the France which preferred to go on judging by customary law (_Droit Coutumier_). This boundary and that of language intertwine, but the influence of big cities as legal centres accounts for some differences. The legal boundary naturally keeps some {28} distance north of the linguistic one near the great southern city of Bordeaux. On the other hand, the influence of valley cities like Clermont-Ferrand helped the northern law to penetrate up the slopes of the Central Plateau, so that the legal boundary is here the more southerly. Lyons, a southern city in so many ways, pushed the legal boundary far to the north of the linguistic one in the Rhone-Saone basin. The boundary line of old-time (pre-1789) Customs Dues, the boundaries of the various Salt Dues (_Gabelles_), of the Governments in existence in 1789, of the general prevalence of the Gothic style in architecture, of the general prevalence of (north) steep-roofed and (south) flat-roofed houses respectively and so on, are all related to the above lines, and can be followed in some detail to work out interesting divergences. The net result of a study of these lines is to show that the French people, apart from the German borderland, consist of two cultural elements, a southern with Roman survivals in cities, language, &c., and a more northern one which is much less Roman. Between them is an intermediate area with mixed allegiance. The study of such a set of boundaries can be given a special value, for it shows us that the linear boundary, however necessary it may be under our outworn system of aggressive states in politics, is an artificiality when applied to the study of peoples. Boundaries are zones, not lines, zones of intermediacy which with better political organization might become interpreters rather than causes of conflict as they have been in the past.