WIDTH AND CROSS-SECTIONS. 287 



with water, the fragments will be displaced by the wheels of 

 carriages and the hoofs of animals, which will crush and grind 

 them together, so that tliey soon become rounded or reduced to 

 powder, and need to be replaced by new material. 



If roads are thoroughly drained, the action of frost upon 

 them would be very much diminished, and the annual breaking 

 up of their surfaces, produced by spring thaws, would be pre- 

 vented. The effect of heavy rains, frequently so destructive to 

 water-soaked roads, would be the most efiiciently guarded 

 against by means of thorough draining. 



Trees and Shrubs on the Roadside. 



The roads should have a free exposure to the action of the 

 sun and the winds, in order that moisture may dry off quickly. 

 Hence, natural hedges and trees ought not to be allowed to line 

 their sides in a way to interfere with this object. The dripping 

 from branches, too, hanging over the road is injurious. 



Besides overshadowing and sheltering the road, shrubs and 

 trees are often allowed to encroach in such a way as to discom- 

 mode the travel. 



Width op Way. 



The width of way between the larger towns, or where the 

 travel is considerable, should be thirty feet, increased, perhaps, 

 to forty feet at a near approach to the towns, but ought never 

 to be less than twenty-five feet. 



The first cost is somewhat greater for a wide track ; but if 

 the width is not extreme, and the surface is properly covered 

 and shaped, the same amount of material will wear much longer 

 than upon a narrow one. 



Upon narrow roads the travel is apt to be confined to one 

 part, thus producing ruts and unevenness, which hastens the 

 wear, while upon a wider one this is not so likely to occur. 



Cross-Section of Roads. 

 The form of cross-section is very important, and one upon 

 which there has been much difference of opinion, some advo- 

 cating a flat surface, others holding that the surface should be 

 very crowning. These latter urge the necessity of making the 

 centre of the road much higher than the sides, because the 



