ROADS AND PATHS 39 



The roller should be started at the side of the road, thus 

 pushing, as the roller moves back and forth, all the sur- 

 face material more or less toward the center. Skillful 

 and persistent rolling, sometimes for weeks together, 

 constitutes a large part of the secret of the construc- 

 tion of a good road, whether it be made of gravel or 

 broken stone and screenings. 



A pernicious way of building roads is often adopted 

 by spreading a thick layer of clayey loam on top of the 

 rubble or stone foundation, to make what is termed a 

 cushion. The difficulty with this kind of work is that 

 clay is liable to work in large quantities to the actual 

 surface of the road, and allow holes to form by settle- 

 ment. A reason for the popularity of this so-called 

 cushion may be found in the fact that it is easy, in this 

 way, to fill with earth, cheaply and readily, the inter- 

 stices of the stones which should have been chinked up 

 with slivers and chips. 



A good rule has been laid down, which may be modi- 

 fied by circumstances, as all rules must be, whereby a 

 road shall have a depth of foundation of rubble or telford 

 of not less than one-half and not more than two-thirds 

 of the entire thickness of the road covering. In this 

 way a road excavated nine or ten inches deep may have 

 a foundation of large stones six inches thick, while seven 

 or eight inches would not be too heavy for a road exca- 

 vated twelve inches deep. The difficulty with a road, 

 the foundation of which is not sufficiently bedded and 

 chinked with chips and spalls, is that a heavily loaded 

 vehicle is liable to tilt up one of these imperfectly bedded 

 stones, and thereby render necessary the reconstruction 

 of the entire driveway at that point. The foundation 

 stone should be of as nearly equal size as possible, vary- 



