We talk of the “potential” between two commercial centres, or between a capital and a port, or between a mineral producing region and an agricultural region, or between a region whence barbarians desire to invade fertile civilized land and the centre of the fertile civilized land which desires to defend itself, etc., etc., and our use of this word “potential” is drawn from the doctrine of physical science that energy in open shape, energy at work, is given its opportunity by the tendency of two points to establish a communication: the tendency of two separate situations to establish unity, the tendency of a hitherto “potential”--that is, only “possible,” not yet “actual”--force to realize itself. For instance, you will have a highly charged electrical area tending to discharge itself by the line of best conduction. You will have a head of water creating a “potential”: a reservoir a hundred feet above the valley has to be connected with the floor of the valley by a tube to turn the potential energy into actual energy and to drive a turbine. Now, in the development of the road system we metaphorically use this word “potential” in just the same fashion. For instance: there was originally no bridge across a river because the people in the town on one side of it had no particular reason to cross to barren land upon the other. The town gradually developed into a holiday resort. The only place for a good golf links was on the far side of the river, and visitors who lived in the town during their holidays wanted to go during part of the day to the golf links. A “potential” was established. Thus there has always been a most powerful “potential” between London and Dover, between the great commercial centre of the island and the port nearest to the Continent. That is a “potential” which has worked throughout the whole of English history. We can watch other potentials at work in different periods arising and dying out again. For instance, during the Norman and early Angevin period there was a very strong “potential” between the middle north coast of France and the coast of Sussex, with a corresponding development of traffic. The principal people in England were also great land owners and officials on the coast immediately opposite. That “potential” died down until the revival of modern steam traffic. Again, there is a “potential” to-day between any coal field and any centre of consumption of wealth distant from that coal field. So there is between any coal field and any great port. Again, you will have a strategic “potential.” A particular point of no economic value may be of the utmost strategic value. The holding of it may make all the difference to the defenders of the frontiers, and in that case a “potential” exists which is the driving motive for a road between the capital and the point in question. With this note in mind we can proceed to some sketch of the history of the English Road. ii