ii
The last main cause modifying the trajectory of a road is the relative proximity of material for its construction, using the word “proximity” in the wider sense to include all economic effort: what to-day we call the “cheapness” of the material.
Even in the very simplest and most primitive form of roadwork material enters. There is always the necessity of hardening some bit of soft ground or of smoothing some bit of unevenness, and from the beginning of travel you have had the transportation of material to the established road for the improvement of its surface, for the bridging of its water obstacles or flooring of fords, for the making of its causeways over marshes.
In what may be called the middle period of road construction—that is, in periods of high civilisation, but civilisation not provided with modern instruments—the immediate neighbourhood of material introduced a considerable modifying factor into the trajectory of a road. This was often masked, from the fact that the same soil which provided good going and therefore developed early tracks usually also provided, in the nature of things, good material for hardening the surface, for the building of causeways, and even for the throwing of bridges. It was also masked by the fact that the bridge, if it were to be built of wood, could get its material from a considerable distance, as the river was its avenue of supply. But though transport of material has gone through a revolution in the last hundred years, and material for road-making is now brought half across the world (e.g. Colonial wood pavement), yet the way neighbourhood of material tells can still be seen everywhere upon the road map of Europe. Thus the absence of main roads in the Fens for centuries was not only due to the necessity of continual artificial work, embankments, and bridges (this would not have deterred the Roman road-makers nor the great effort of the early Middle Ages from attempting a full network of roads). It was rather due to the absence of hard material. And you have the same phenomenon in the Landes of South-western France, where to this day only one great road serves an immense district whose loose and sandy soil fails to provide a cheap and sufficient material. The traveller in Holland notices the same thing: here are roads ultimately depending upon brick paving and narrow, where, had there been abundant material available, they would have been broad, for they had to carry a great deal of traffic. The alternative water traffic by their side was largely developed by the difficulty of making the road.
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.