456 FUNDAMENTALS OF AGRICULTURE. 



transportation, even but a small per cent., would re- 

 sult in a large saving to the country. 



By far the largest portion of the roads of the 

 United States are earth roads aggregating about 

 2,000,000 miles.* It is thought that it will be many 

 years before even a small proportion of these roads 

 can be improved by surfacing with some other mate- 

 rial suitable for road building. For this reason, the 

 subject of earth road construction and maintenance is 

 of great importance to all interested in rural develop- 

 ment. 



EARTH ROAD CONSTRUCTION. 



The subject of earth roads readily divides itself 

 into two main divisions : first, earth road construction 

 the building or making of the roads, and second, 

 earth road maintenance the care of the road after it 

 is made. The ideal road of any material is con- 

 structed and maintained so as to be as hard, level and 

 smooth as possible. An earth road is best when it 

 is made to comply with these requirements. Water, 

 either directly or indirectly, is the most destructive 

 agent of earth roads, and their construction consists 

 primarily in excluding the water from the road or, in 

 other words, providing drainage. 



The Crown. If water is allowed to remain on the 

 surface of an earth road, it softens the surface and 

 destroys that fundamental characteristic of a good 

 road, its hardness or firmness. If the surface of a 

 road is earth, it will absorb the water that comes to 

 it in the form of rain or snow, and will be converted 

 into mud unless the water is shed to each side as soon 

 as possible. The slope or oval shape given to a road 

 for this purpose is called the crown. The slope of 

 the crown must not be too steep to make it dangerous 

 for vehicles to pass, but it should be steep enough to 

 shed the water as quickly as possible. The usual 



* Farmers' Bui. 321 U. S. Department of Agriculture. 



