CH. X STONE PAVEMENT IJJ 



' The stone selected must be one which wears 

 ' rough and gritty, and does not polish and become 

 ' slippery. The softer stone will not wear so long 

 ' as the hard one, but that must be submitted to. 



' The asphalt serves three purposes : it closes the 

 'joints, and prevents any water passing through 

 ' the pavement to the concrete or the subsoil, which 

 1 is necessary to the maintenance of a good pave- 

 ' ment ; it prevents dust rising from the joints ; and 

 ' it fills the top of the joint so as to prevent, to 

 ' some extent, the rounding of the upper surfaces 

 ' of the stones by the continued impact of the 

 ' wheels, which is the way that the best laid pave- 

 ' ment finally becomes rough and noisy. There is 

 ' no remedy for this other than turning the stones 

 ' upside down, or re-cutting their upper surfaces, 

 ' and using them on streets admitting of a thinner 

 ' pavement. 



' The asphalt diminishes the noise by preventing 

 ' the wheels from striking- the edges of the stones 

 ' with as much force as if the joints were open, and 

 ' it can be renewed during any hot, dry weather at 

 ' a small cost. It must be poured into the joints 

 ' neatly from a ladle, or equivalent device. 



' At street intersections, it is best to carry each 

 ' line of paving to a point in the intersection, to 

 ' avoid, as far as possible, the longitudinal joints 

 ' being in the direction of the traffic. 



' Continuous lines of joints in the direction of the 

 ' traffic are fatal to the maintenance of a ge>od 



12 



