DUST PEEVENTION AND EOAD PEESERVATIOlSr, 1915. 

 Table 46. — Cost data, bituminous limestone. 



45 



Item. 



Total 



cost. 



Cost per 



square 

 yard of 

 surface. 



Item. 



Total 

 cost. 



Cost per 

 square 

 yard of 

 surface. 





$45. 15 

 48.82 

 77.84 

 86.84 

 51.31 



179.80 

 10.00 



42.05 

 8.65 



108.06 



$0.0247 

 .0266 

 .0424 

 .0473 

 .0280 

 .0980 

 .0055 



.0230 

 .0047 



.059 



Freight on oil 



$57. 44 

 8.80 

 24.52 



8.80 

 47.56 

 52.41 



$0 0313 



Subgrade .". 



Hauliag oil to road 



.0048 



Shoulders 



Heating and applying oil 



Hauling, screening, and 



.0133 







Quarrying, explosives 



.0048 



Rolliag (including cost of coal) 

 Incidentals and supervision. . . 



Total cost 



.0258 



Spreading base course 



Screening limestone for wear- 



.0286 



858.05 

 780.21 



.4674 



Spreading wearing course 



Asphaltic oil; 1,801 gallons, 

 f. 0. b. Baltimore, Md 



Total (exclusive of shoulders). 



.425 



Table 47. — Cost data, sand-asphalt. 



Item. 



Total 

 cost. 



Cost per 

 square 

 yard of 



surface. 



Item. 



Total 

 cost. 



Cost per 

 square 

 yard of 



surface. 





$34.80 

 25.01 

 119.60 



418. 70 

 14.77 



310. 00 

 67.02 



192.09 

 70.30 



$0.0282 

 .0203 

 .0969 



.3393 

 .0120 

 .2512 

 .0543 

 .1557 

 .0570 





$39. 56 

 5.45 



$0 0320 



Subgrade .". 



Hand rolling 



.0044 







0168 



Asphalt, 21.77 tons, including 

 freight 



Total cost 



20.75 

 1,318.05 

 1,198.45 



1,163.65 





1 0681 



Hauling asphalt (3i miles) — 

 Screening and heating sand. . . 

 Heating asphalt 



Total (exclusive of shoulders) . 

 Total (exclusive of rough grad- 

 ing and shoulders) 



.9712 

 9430 



Mixing sand and asphalt 



Transporting mixture 







SUPPLEMENTARY REPORTS ON EXPERIMENTS PREVIOUSLY 



REPORTED. 



The experiments which were in progress at the beginning of the 

 year have all been described in previous pubHcations of the Office, 

 and reference is made to these pubUcations by number, in the descrip- 

 tions below. It will be noted that the experiments undertaken at 

 New York, N. Y., and Ridgewood, N. J., in 1910; at Boise, Idaho, in 

 1910, and at Newton, Mass., in 1908, have all been discontinued. As 

 explained in Department Bulletin No. 257, the reasons for dis- 

 continuing these experiments were either that they have proved 

 failures or that subsequent improvements have destroyed their 

 value from the standpoint of furnishing comparable results. 



SUPPLEMENTARY REPORT OF EXPERIMENTS AT LEMON CITY, FLA., 1914. 



onus, TAK PREPARATION, CALCIUM CHLORIDE-CORALLINE ROCK. 



The original report of the details of construction of these experi- 

 mental sections was published in U. S. Department of Agriculture 

 Bulletin No. 257. 



In July, 191 5, a surface treatment of asphaltic material was ap- 

 plied uniformly to aU the sections by the county road authorities. The 



