Stone Roads. 



479 



exceed 10 inches in length, inches wide <>n the bottom 

 and 4 inches at the top, the thickness being 4 pr ."> inches 

 for a road S inches thick. The surface of the pavement 

 foundation should be as even as practicable and the voids 

 filled with broken stone. It is necessary to have each piece 

 thoroughly bedded before the macadam material is added 

 so as not to be tilted on the surface. 



FIG. 230. View showing road with the stone portion in the foreground nearly 



completed. 



597. Culverts Culverts are necessary for carrying un- 

 der a road the water from adjacent fields which colled 

 surface drainage in times of heavy rains and melt ing snows. 

 The permanent forms are made of sewer tile, cement tile, 



