366 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1934 



The system of Gallic-Roman roads lasted from the fall of the 

 Empire of the West, in A. D. 476, until the middle of the seventh 

 century. The roads as a system seem to have disappeared gradually 

 in the following century. With the rise of the feudal system on the 

 Continent, the Roman roads were destroyed because the people saw 

 in them a means of transportation for robber bands and conquering 

 armies. Thus, under the chaotic political conditions which prevailed 

 during the Middle Ages, roads fell into disuse and repairs were 

 neglected. 



In England, with the Anglo-Saxon invasion in the fifth century, 

 there began a period of 1,400 years of neglect and spoliation of the 

 Roman roads. English names were given them and they were attrib- 

 uted to a fabulous origin. The greatest destruction of the Roman 

 roads, however, occurred in the eighteenth century, when they were 

 robbed of their materials and destroyed in order to make the turn- 

 pikes. The roads which escaped the ravages of man seem to be little 

 affected by the centuries of neglect {H). They are found generally 

 under an accumulation of soil which acts as a protective covering 

 and an aid to their preservation. 



MODERN ROAD CROSS SECTION MORE ECONOMICAL THAN THAT OF 



THE ROMANS 



At the close of the Middle Ages, when social conditions became 

 sufficiently stabilized to permit the resumption of road building 

 under the supervision of organized governments, the cross sections 

 of the roads bore a strong resemblance to those employed by the 

 ancient Romans. Thus the designs adopted by Tresaguet, in France, 

 and Telford, in England, as shown in figure 6, with their subbases 

 of large stones, are a reversion to the heavy statumen course of the 

 Roman road builders. Toward the close of the eighteenth century 

 the idea that the subgrade soil was the sole support for the weight of 

 traffic was still in its embryonic stage. 



It was not until the early part of the nineteenth century that John 

 Loudon Macadam, the English road builder, eliminated the heavy 

 Telford subbase, which harked back to Roman times, and substituted 

 in its place a base course composed of broken stone with a maximum 

 weight of 6 ounces (approximately 2i/2 inches in size). Thus it was 

 Macadam who argued that "all the old roads of the kingdom have 

 been OVERDONE " and proceeded resolutely to omit the heavy stone 

 subbase from the roads built under his direction {15). His philos- 

 ophy, which at that time was considered quackery by some, was as 

 follows: "The roads can never be rendered thus perfectly secure 

 until the following principles be fully understood, admitted, and 

 acted upon: namely, that it is the native soil which really supports 



