The subject of this article opens to us so vast a field of inquiry, that it is impossible to do justice to its importance within the limits prescribed to us. To the curious explorer of ancient records, a search into the history of roads, from the earliest ages of antiquity, would repay his utmost labour. While to the philosopher it offers ample scope for meditation and reflection; the theorist may speculate on the influence, moral and political, exercised by facility of communication between distant members of the same body politic; and the sound reasoner find, in the opening of good roads alone, data on which to base a true estimate of the progress of society.
Roads may be described as both the cause and effect of civilization; the formation of roads invariably tending to improve the most barbarous district, to evolve its resources, and civilize its people; while, on the other hand, the internal communications of a country afford the surest proof of her prosperity; and her roads, the infallible signs, because the certain consequences, of her civilization. "Let us travel," says the Abbe Raynal, "over all the countries of the earth, and wherever we find no facility of travelling from a city to a town, or from a village to a hamlet, we may pronounce the people to be barbarians." "The making of roads," observes Sir Henry Parnell, in his admirable Treatise, "in point of fact, is fundamentally essential to bring about the first change that every rude country must undergo, in emerging from a condition of poverty and barbarism."
The wise policy of the Romans taught them to lay open the countries they subdued, which might afford an easy transport of their ammunition and supplies. In Britain, some remains of the Roman roads are yet visible. At Chester, remnants of the old Roman pavement, called the Castrum, are frequently discovered on removing the superincumbent soil; in Scotland, a portion of Roman causeway, leading from Musselburgh Bay to Abercorn; in the neighbourhood of St. Albans on the road to London - and in many other places. All the roads discovered ran nearly in direct lines. Natural obstructions were removed or overcome by the efforts of labour and art, whether they consisted of marshes, lakes, rivers or mountains. In flat districts the middle part of the road was raised into a terrace. In mountainous districts the roads were alternately cut through mountains and raised above the valleys, so as to preserve either a level line, or a uniform inclination. They founded the road on piles where the ground was not solid, and raised it by strong side walls, or by arches and piers, where it was necessary to gain elevation. The paved part of the great military roads was 16 Roman feet wide, with two side ways, each 8 feet wide, separated from the middle way by two raised paths, 2 feet each.
At every mile columns were erected, to mark the distance from place to place; blocks of stone for foot travellers to rest upon, or for horsemen to mount their steeds with; temples, triumphal arches, and mausoleums adorned them, and military stations defended and commanded. By the formation of these great highways, an impulse was given in Britain to the national industry. The genius of the British people, essentially commercial, hastened to avail itself of the facilities (limited as they were) for intercourse and traffic; and we may fairly attribute to the conquest of Britain by the Romans her present commercial superiority.
A road should combine the qualities of hardness, smoothness, and strength or solidity. To obtain these requisites, it appears to us indispensable that great care should be taken to prepare the foundation for the materials; but on this point much diversity of opinion exists; Mr. M'Adam maintaining that the elasticity of the subsoil is rather a benefit than an injury, in contradiction to the opinion of Mr. Tredgold, and other eminent engineers, that on a substratum of a spongy nature, as bog-land, or morasses, it is imperative to render the foundation firm.