The Romans fought this difficulty with singular tenacity. They made all their great public constructions to last, as it were, for ever; and they made their roads with such a strong political and military object that they would not be deterred save, as in the Fenlands, by the gravest difficulties in the obtaining of material. Thus in such of their roads as start anywhere near a sea-beach of shingle you will find them using that material up-country for miles, and they will make deep foundations for roads that have to cross clay, using, sometimes, hard stone brought over a couple of hundreds of miles of sea and some thirty of land travel. It is a difficulty which has not disappeared to-day. It has been very greatly lessened by modern means of transport, but it still appears. We see it throughout modern Europe: for instance, in the varying surfaces of the different soils. The ideal surface of broken granite is not nearly universal even in England, as one would think modern transport would have made it long ago, over such a small area with such masses of granite close at hand and accessible by sea. The relative cost of transport still makes diversity of surface the rule. One can make a sort of economic barometer based on the use of granite. It extends farther and farther from the sources of supply as public wealth expands, and recedes towards them as public wealth diminishes. We have a first-class example of this in the case of flint versus granite. Flint has its advantages over all other material in hardening a roadway. It is at once hard and easily broken: it is superficial, and therefore cheap: it is abundant in supply in the districts where it is used. On the other hand, it has the gravest possible disadvantage for modern motor traffic, which is its effect upon the tyres indispensable to that traffic. One could draw a graph, I think, to cover the last ten years showing the fluctuations of this material and granite upon the main roads of Southern England, and the curve would follow the opportunities of supply and of public expenditure as affected by the Great War. CHAPTER V POLITICAL INFLUENCES _The Factor of Cost Resulting in the “Strangling of Communication”: Congestion which Leads to Decay: A Great Modern Problem: The Compulsory Acquisition of Land: Old Roads Serving New Objects._ i So far we have been considering the material conditions of the Road: the physical circumstances which determine its trajectory. But these alone do not completely account for its trace in practice or theory. There is another category affecting this, the political or moral category: the various effects of society in modifying what, but for them, would be the formula of least effort. These political causes of modification are of less effect than the physical, but they merit a brief mention.