148 



THE PAKKS AND GARDENS OF PAIUS. [Chap. IX. 



The postles used in pressinf^ it are of cast-iron, circular, and al)ont 

 eight inches in diameter. The pestles of either form" are heated 

 and used quite hot, so as to compress the asphalte into a hard 

 smooth mass. 



When the crust of asphalte is brought to the thickness required, 

 and is sufficiently smoothed and heaten hard, a little quantity of 

 very fine powder is sj)read with a sieve to fill all the unevenness, 

 and the whole is again smoothed with a flat piece of hot iron. 

 The compression is completed by the employment of two cast-iron 

 rollers, one of 40001b. weight and the other of oOOOlb, Sometimes 

 three of these rollers are employed, the intermediate one being 

 about 15001b. or 16001b. in weight. This rolling is not always 

 necessary, in many cases the beating down with pestles being 

 sufficient. The roads thus made, completely noiseless and lasting 

 a long time, have been adopted with the greatest success by the 

 city of Paris, and are supplanting the paving-stones, macadamized 

 and other pavements in many narrow streets. 



