OBJECT-LESSON AND EXPERIMENTAL ROADS, 1912-13. 27 



$0,035 per bushel, while the remaining 21,825 bushels cost $0,045 delivered at 

 the Naval Academy docks. 



The total cost of the work, exclusive of depreciation and fuel for the roller, 

 was $2,803.11, making the cost per square yard $0.19. The principal items of 

 cost were as follows : Excavation, 1,037 cubic yards at $0.30 per cubic yard, 

 $310.44; shaping the subgrade, $236.76; surfacing material delivered on the 

 road, 24,300 bushels, at $0,035 per bushel, $850.51 ; surfacing material delivered 

 at the docks, 21,825 bushels, at $0,045 per bushel, $982.12 ; hauling the surface 

 material, $110.40 ; spreading the surfacing material, $156.44 ; rolling the surface, 

 $155.16 ; and incidental expenses, $1.28. 



EARTH ROADS. 



Pangbusn, Aek.^ — Work was begun on the River Road leading from Pang- 

 burn toward Cleburne County on September 2, 1912, and was completed on 

 September 13, 1912. An earth road 1,000 feet long was constructed 30 feet 

 wide. 



The country is hilly and the natural soil from station to station 8 is clay 

 containing sandstone and shale. From station 8 to station 10, on the west side 

 of the road, it is also clay and rock, but on the east side the soil is loam. There 

 was no center cut and the maximum fill was 2 feet. The maximum grade re- 

 mained 10 per cent, as it was before the improvement. The earth was loosened 

 with a plow and picks, hauled in drag scrapers, and spread with shovels and a 

 road grader. The presence of loose rock in the clay made excavation difficult. 

 It was removed with picks and a bar by hand labor. The maximum haul was 

 120 feet and the average haul 40 feet. A retaining wall 27 feet long was built 

 at station 8. It was made of the stone obtained in excavating and laid dry. 



The equipment consisted of a road grader, a road plow, and hand tools, all of 

 which were in poor condition. Labor cost $0,125 per hour, and teams cost $0,375 

 and $0.25 per hour. The total cost of the road was $166.75, which is at the 

 rate of $0.05 per square yard, or $880.44 per mile. The principal items of cost 

 were as follows : Clearing and grubbing, 3,333 square yards, at $0,005 per 

 square yard, $17; earth excavation and embankment, 500 cubic yards, at $0.18 

 per cubic yard, $90; rock excavation, 42| cubic yards, at $1 per cubic yard, 

 $42.75 ; fine grading, 3,333 square yards, at $0.0044 per square yard, $14.50 ; and 

 retaining wall, 5 cubic yards, at $0.50 per cubic yard, $2.50. 



Zona, Fla. — Work was begun on February 4, 1913, on a road leading east- 

 ward from the State canal, about one-half mile above Zona. The road was 

 built between and parallel to two tributary ditches to this canal, which were 

 about 40 feet apart, and the material excavated from the ditches was used 

 in grading the road. The work was in the nature of an experiment, having 

 for its object the development of a satisfactory road surface composed of the 

 native black muck, muck and sand, or coralline rock. The road is in the 

 Everglade district, and the material obtained from the ditches was of three dis- 

 tinct types. The top soil, to the depth of from 2 to 5 feet, was black muck, 

 which is in reality decayed organic matter, finely honeycombed, very light and 

 fluffy when dry, and very difficult to consolidate. Below this muck a layer of 

 fine sand was encountered varying in depth from 1 to 3 feet. The formation 

 below the sand was coralline rock. 



The section of road improved was 6,800 feet long and 18 feet wide, making 

 a total area of 13,600 square yards. 



It was originally intended that the first 2,000 feet would be surfaced with 

 coralline rock obtained from the banks of the State canal, and that the remain- 

 ing distance should be divided into two experimental sections, the first to be 

 surfaced with muck or loam, which was to be consolidated by a light tamping 



