172 TELFORD CH. X 



regards, and especially as being the more easily 

 repaired, acknowledging, however, that it is more 

 likely than the Telford road to become rutted when 

 the frost is coming out of the ground. 



For a Telford road of the best quality, the bed, 

 formed 12 to 16 inches below the intended surface 

 of the finished road, should be carefully graded with 

 a slope from the centre toward the sides, and 

 thoroughly drained by tile, shallow broken stone, 

 or gravel drains. No road of any system can be 

 good or lasting unless it is thoroughly drained ; 

 this is absolutely essential. Upon the bed thus pre- 

 pared, a paving of one layer of stones, from 7 to 

 10 inches deep, is laid by hand. Each stone must 

 be laid with its widest face on the bed, the object 

 being to prevent the stones from being pressed into 

 the ground, and to distribute the pressure from 

 passing wheels over as large a surface as possible. 



Fig. 76. 



Since the stones should touch each other where 

 they rest on the ground, the upper surface will be 

 broken by irregular openings which must be packed 

 tightly with stone chips. Upon this rough pave- 

 ment, which may be made of any inferior stone, not 

 too soft, is spread the hardest stone procurable, 

 broken to sizes of from 1 x / 2 to 2 inches, to a depth 

 of from 4 to 8 inches and well rolled with a steam 



