662 TRANSACTIONS OF THE 



vals, with underdrains. And where the ground is exceedingly 

 soft, cover it with a layer of brush from six to eight inches in 

 depth, before the road materials are put on, or your labor will 

 be thrown away. 



The ancient Romans constructed their military road in France, 

 by forming a foundation of concrete, according to our second 

 class, composed of gravel and lime, upon which they placed a 

 pavement of large stones; and they have endured the wear* and 

 tear of fifteen hundred years. 



A concrete may be made of gravel and lime, in the proportion 

 of four gravel, to one lime, made upon the road, and spread to 

 the depth of five or six inches, according to the trafl5.c; cover this 

 with five or six inches of coarse gravel, before the concrete 

 hardens; when in a few hours the two beds will unite and 

 become perfectly hard from the complete wedging ol the coarse 

 pebbles together. 



The third plan is to pave a road with stones, thus : commence 

 at the sides and lay a layer of stones two and one-half inches in 

 depth, and gradually increase until you reach the centre. Say 

 fifteen feet from the commencement, where, let them be seven 

 inches in depth, and graduate them to the opposite side in the 

 same manner. Then break off all projecting inequalities, and 

 fill up the spaces with stone chips, placed by hand, and wedged 

 in with a light hammer. And that there may be no misappre- 

 hension with regard to the stones used for wedging, I would state 

 that they must be angular; as round pebbles would not answer 

 the purpose at all. 



Then again an admirable road may be formed with angular 

 stones alone, which may be obtained by breaking up granite, or 

 the liard pebbles usually found on the shores of streams. The 

 harder they are, of course the better, as sandstones, ordinary 

 limestones, &c., would not resist the action of heavy wheels. 

 After the road is properly trunked, spread these angular stones 

 on to the depth of, six or seven inches, and cover them with 

 coarse gravel to the depth of two inches, if the travelling public 

 grumble; but if they are good natured, and will inconvenience 



