590 EXPEEIMENT STATION EECOED. 



lishiiig the grade lines of a farm drainage system are drescribed, and it is 

 suggested that a surveyor be employed to test the final survey. 



A simple and economical method of burning lime, J. H. Arnold and J. B. 

 Nichols (U. 8. Dept. Agr., Bur. Plant Indus. Circ. 130, pp. 19-23, figs. 3). — 

 This paper gives the results of lime-burning experiments on a farm in Warren 

 County, Kentucky. The kiln was located on top of a bed of limestone, the 

 greater part of which was exposed at or very near the surface. Poles and slabs 

 were placed lengthwise on the ground, making a layer 30 ft. long and 16 ft. 

 wide. The largest poles, 8 or 10 in. in diameter, were used for the outside rows 

 in order to make a more stable foundation. The smaller poles and slabs were 

 placed between the large outside poles, and these made up the layer except for 

 a strip 2 ft. wide in the middle, where smaller wood and kindling were placed 

 the entire length of the kiln. Chinks between the poles and slabs were filled 

 with fine wood and cornstalks. Fine coal was then placed as a second layer 

 to a depth of 2 in. On the top of it was placed a 4 or 5 in. layer of crushed lime- 

 stone on which another layer of coal was added, this being followed by a 12 

 to 14 in. layer of limestone. Alternate layers of coal and stone were then added 

 to these until the pile was 7 or S ft. high and was then shaped off into a pyra- 

 mid. The fire was started on the windward end near the middle, and the burn- 

 ing continued about two weeks. The dirt was then removed to allow the rains 

 to slake the lime. The total cost of burning the 87 tons of lime in this kiln 

 was $80.10. On a similar kiln of the same dimensions the total cost was $93. 



Progress reports of experiments in dust prevention and road preservation, 

 1912 {U. S. Dept. Agi:, Office Pub. Roads Circ. 99, pp. 51). — The completed ex- 

 periments as begun in 1911 at Chevy Chase, Md. (E. S. R., 28, p. 383), of treat- 

 ing the surface of a waterbound macadam road with bitumens are as follows: A 

 section comprising 1,477 sq. yds. was cold-treated with 0.54 gal. per square yard 

 of refined water-gas tar preparation on which was spread i to 1 in. limestone 

 chips at the rate of 0.014 cu. yd. per square yard. A section comprising 761 

 sq. yds. was cold-treated with 0.53 gal. of asphaltic petroleum per square yard. 

 After 6 hours this was covered with i to 1 in. limestone chips at the rate of 1 

 cu. yd. for every 72 sq. yds. A section comprising 1,013 sq. yds. was treated 

 with hot residual petroleum under 00 lbs. pressure, which was immediately 

 covered with screenings. The total cost per square yard for these treatments 

 were, respectively, 7.01, 9.43, and 11.73 cts. An inspection of these surfaces in 

 February, 1913. showed them to be in fair condition, yet with some wear which 

 will require additional treatment. A section comprising 388 sq. yds. of the same 

 surface was resurfaced with native asphalt emulsion and fine trap screenings 

 mixed, containing 10* gal. emulsion to 4 cu. ft. of screenings. This was applied 

 to a thickness of 2i in. at a total cost per square yard of 81.51 cts., including 

 rolling and preparing the old surface. 



In 1912 experiments at Chevy Chase, Md., in which sections of bituminous, 

 cement, and oil-cement concrete were constructed, were as follows : A section 

 comprising 1,498 sq. yds. was constructed of bituminous concrete (Topeka 

 specifications), the surface layer being laid upon a 6 in. cement concrete founda- 

 tion of a 1:3:7 mixture. The bituminous concrete layer was laid on the base 

 after 1 month to a thickness of 2 in. after rolling and finished by a light cover- 

 ing of Portland cement. Two mixtures of bituminous concrete were used, the 

 first consisting of 7.6 cu. ft. of limestone screenings to 8.8 gal. of asphalt cement 

 and 50 to 70 lbs. of limestone dust ; and the second consisting of S cu. ft. of trap- 

 rock screenings to 9.3 gal. of asphaltic cement and 60 lbs. of limestone dust. A 

 section of bituminous concrete (District of Columbia specifications) compris- 

 ing 1,400 sq. yds. was laid in the same manner, using 2 bituminous concrete 

 mixtures, the first consisting of 7.6 cu. ft. of crushed limestone to 4 cu. ft. of 



