322 FARM DEVELOPMENT 



ditches " may be used to allow a sharper crown to be 

 made in a narrow roadway in the center of the wide 

 grade. Small spade ditches from these top ditches will 

 carry the water to the drainage ditch below and, by 

 proper management, the area between the top ditch and 

 the main ditch can often be used for travel. In level 

 countries made up of fine clay which is likely to drift be- 

 fore the wind and leave a deposit in the large ditch along 

 the sides of the road, these top ditches sometimes serve 

 as a temporary expedient in repairing the road until 

 such time as the main drainage ditches can be cleaned 

 out and the grade dressed up anew. Top ditches may 

 sometimes be advantageously used between the main 

 roadway and the bicycle path to prevent teams being 

 driven on the grassy or improved bicycle path on the slope. 



CONSTRUCTING THE ROAD SURFACE 



A complete catalogue of the materials used for sur- 

 facing roads would be extensive. The attempt here will 

 be to discuss only the several groups of these materials. 



Common earth and sand are, of necessity, as yet, more 

 used for roadways than are all other classes of materials, 

 since the soil or subsoil thrown up beside the road is 

 easiest utilized for the roadbed. Soils composed largely 

 of clay, when wet, are so soft, so easily cut into deep 

 ruts, and cling so tenaciously to the wheels of vehicles 

 and to the feet of animals, that they are the most 

 unsatisfactory of all raw materials ; yet when dry and 

 hard they make most excellent roads. Fine sand, 

 on the other hand, is nearly as objectionable as soft 

 clay. The sand becomes pulverized when dry, allow- 

 ing the wheels of vehicles to sink so deep that they 

 are dragged forward with great labor by draft animals 

 which have a poor footing; bicycles and motor vehicles 

 traverse such roads with great difficulty. When clay 



