Mr. M' Adam's Improved St/stem of Road- Making. 



1823.] 



London are formed is the worst ; because it 

 is mixed with a large portion of clay, and 

 because the component parts of gravel are 

 round, and want the angular points of con- 

 tact, by which broken stone unites, and 

 forms a solid body. The loose state of the 

 roads near London is a consequence of this 

 quality in the material, and of the entire 

 neglect, or ignorance of the method, of 

 amending it. 



A road near London may be made as 

 smooth, solid, and easy for cattle to draw 

 carriages over, as the road near Bristol; 

 and the London road so made will last 

 longer, and consequently be less expensive, 

 than the Bristol road, because the materi- 

 als which may be obtained are more dura- 

 ble, and may be procured at less expense. 



Flint makes an excellent road, if due 

 attention be paid to the size ; but, from 

 want of that atttcntion, many of the flint 

 roads are rough, loose, and expensive. 



Limestone, when properly prepared and 

 applied, makes a smooth solid road, and 

 becomes consolidated sooner than any 

 other material ; but, from its nature, is not 

 the most lasting. 



Whinstone is the most durable of all ma- 

 terials; and, wherever it is well and judi- 

 ciously applied, the roads are compara- 

 tively good and cheap. 



The pebbles of Shropshire and Stafford- 

 shire are of a hard substance, and only re- 

 quire a prudent application to be made 

 good road materials. 



On the other h^nd, the Scottish roads, 

 made of the very best materials, which 

 are abundant and cheap in every part of 

 that country, are the most loose, rough, 

 and expensive, roads in the United King- 

 dom, owing to the unskilful use of the 

 material. 



The formation of roads is defective in 

 most parts of the country; in particular 

 the roads round London, are made high in 

 the middle, in the form of a roof, by which 

 means a carriage goes upon a dangerous 

 slope, unless kept on the very centre of the 

 road. 



These roads are repaired by throwing a 

 large quantity of unprepared gravel in the 

 middle, and trusting that, by its never con- 

 soUdating, it will in due time move towards 

 the sides. 



When a road has been originally well 

 made, it will be easily repaired. Such a road 

 can never become rough, or loose ; though 

 it will gradually wear thin and weak, in pro- 

 portion to the use to which it is exposed ; 

 the amendment will then be made, by the 

 addition ofa quantity of materials prepared 

 as at first. As there will be no expense on 

 snch road, between the first making and 

 each subsequent repair, except the neces- 

 sary attention to the water-ways, and to 

 accidental injuries, the funds will be no 

 longer burdened with the unceasing expen- 

 diture, at present experienced, from con- 



123 



tinual efforts at repairing, without amend- 

 ment of the roads. 



Obseixations by John Loudon IWAdam, pre- 

 sented to a Committee of the House of 

 Commons, June 14, 1811. 

 1. That the present bad condition of the 

 roads of the kingdom is owing to (lie inju- 

 dicious application of tlie materials with 

 which they are repaired, and to tlie defec- 

 tive form of the roads. 



a. Tliat the introduction of a better 

 system of making the surface of roads, and 

 the application of scientific principles, 

 which has hitherto never been thought of, 

 would remedy the evil. 



In illustration of these positions, I beg 

 to observe, that the object to be attained 

 in a good road, as far as regards the sur- 

 face, is to have it smooth, solid, and so flat 

 as that a carriage may stand upright ; these 

 objects are not attained by the present 

 system, because no scientific principles are 

 applied ; but it is presumed they are per- 

 fectly attainable in all parts of the 

 country. 



Stone is to be procured in some form in 

 almost every part of the kingdom, and a 

 road made of small broken stone to the 

 depth of ten inches, will be smooth, solid, 

 and durable. 



The materials of which the present roads 

 are composed, are not worn out ; but are 

 displaced by the action of the wheels t-f 

 carriages upon stones of too large a size : 

 the wheel does not pass over the materials 

 of which the road is formed, but is con- 

 stantly, almost at every step, encountering 

 an obstacle which must either give way 

 and be removed, or the carriage must be 

 lifted by the forr.e of the cattle so as to 

 surmount it ; in either case the road is in- 

 jured, and the carriage impeded ; and the 

 injury and impediment will be great in 

 the exact proportion to the number and 

 size of the obstacles. 



The size of stones for a road has been 

 described in contracts in several different 

 ways, sometimes as the size of a hen's egg, 

 sometimes at half a pound weight. These 

 descriptions are very vague, the first being 

 an indefinite size, and tJie latter depending 

 on the density of the stone used, and nei- 

 ther being attended to in the execution. 

 The size of stone used on a road must be in 

 due proportion to the space occupied by a 

 wheel of ordinaiy dimensions on a smooth 

 level surface : this point of contact will be 

 found to be, longitudinally, about an inch ; 

 and every pijece of stone put into a road, 

 which exceeds an inch in any of its dimen- 

 sions, is mischievous. 



The roads in Scotland are worse tlian 

 those in England, although materials are 

 more abundant, of better quality, and la- 

 bour at least as cheap, and the toll-duties 

 are nearly double ; this is because road- 

 making, that is, the surface, is even worse 

 understood in Scotland than in England. 



By 



