GRAVEL TOP ROADS. 231 



The cranks m, working the screws w, operate the scrapers I, 

 which are used to keep the roller clean in muddy weather. 

 The frame A, is made heavier at o, so as to have increased weight 

 there to balance the whole frame-work in turning around. The 

 support p, and the guide wheel k, might be dispensed with. A 

 great saving in time and in movements hurtful to the road is 

 effected by making the frame circular as described, this allowing 

 the roller to be turned with the greatest ease. The dimensions 

 are figured on the drawing. A roller of this kind four and one- 

 half feet in diameter and three and one-half feet long, and 

 weighing some four tons when empty, would cost perhaps |560- 

 1600 ; one 5 feet X 3' 8", weighing about five and one-quarter 

 tons (empty,) some $700-1750. Leaving off the break would 

 diminish the cost about $50. 



Before leaving the subject of macadam top roads, it ought to 

 be mentioned, that a bed of rubble stone 10" or 12" deep, merely 

 spread uniformly over the road-bed as a foundation, is better 

 than nothing at all, but can never make the same quality of road 

 as the rough paving described above. 



The following data are to be used in estimating the cost of the 

 kind of readjust described. Rough foundation paving, pieces 

 6"-6" long, filling up crevices and ramming the whole with hand 

 rammers, costs after the material has been brought to the spot, 

 one day's work of a common laborer for every four square yards, 

 this assuming that the paver gets one and two-thirds common la- 

 borer's wages. Same kind of paving if set in sand will cost one 

 day's work of a common laborer for every two and one-quarter 

 square yards. 



To make macadam by hand costs, for sizes from l^-l^" of 

 very hard rock, one day's work for every 0.6-0.44 cubic yards, 

 for less hard rock, one day's wages will make 0.7-0.6 cubic 

 yards, and of soft rocks 1.76-1.17 cubic yards. 



To spread 14-12 cubic yards of macadam is also about a day's 

 work. 



Gravel Top. — Instead of the macadam top described in the 

 preceding articles, screened gravel may be used. These roads 

 are the favorite ones in Central Park, New York, and are prob- 

 ably the best road there is for pleasure drives. It is a matter 

 of some doubt yet whether they do as well for heavy trucking as 

 they do for light vehicles. The foundation for these gravel roads 



