SHAPE OF THE ROAD-BED. 47 



striking and common mistakes in the mending and care of 

 country roads, faults which seem to arise from a want of knowl- 

 edge of the first principles of road-making on the part of those 

 intrusted with the supervision of the highways. 



And first, with regard to the shape of the road-bed. Over a 

 gravelly and hilly country, and over a flat country with a stiff 

 or clayey soil, no one would hesitate to say that the road-bed 

 should be raised above the level of the sides, and crowned suf- 

 ficiently to shed the water ; but the error, astonishingly preva- 

 lent, and indicated, adopted and approved by the writers of a 

 large proportion of the thirty essays alluded to, many of them 

 practical surveyors of town highways, is to finish them in a con- 

 vex curve forming an arc of a circle with the centre raised a 

 foot and often eighteen inches or more, and the curvature at 

 the sides so abrupt as to make it dangerous to turn out on 

 meeting S, carriage, and always giving the driver a feeling of inse- 

 curity. I do not refer to the elevation above the surrounding 

 laud, but simply to the shape of the road-bed, the elevation of 

 the centre above the sides, or what might be called the " trans- 

 verse profile " of the travelled part of the road itself. 



To show that this is no uncommon occurrence I may mention 

 that the county commissioners of one of our large counties, 

 only two or three years ago, in making the specifications for a 

 road only twenty feet wide, required that the road should " crown " 

 in the centre no less than eighteen inches, or one and one-half 

 in. ten, and no amount of reasoning could lead them to reduce 

 this enormous convexity. Is it not time for the law to step in 

 and define what the transverse profile of a road ought to be for 

 a given width ? 



Let us see the results of this serious error. The convexity is 

 so great that the centre of the road is the only place where a 

 carriage stands upright. The travel, therefore, clings to the 

 middle of the road, wearing one path for the horse and two 

 ruts for the wheels, wearing the road down very unevenly. 



The water, therefore, invariably stands on the middle of the 

 road, while it is constantly washing away the sides. A road 

 ought to be formed so as to induce travel over all parts of it. 

 But with this great convexity, whenever a carriage is compelled 

 to turn to the sides it causes great additional wear on account of 

 sliding down the sides, while by this sliding tendency, being at 



