26 BfLLETIX 347, I". S. DEPAETMEXT OF AGBICTJLTUKE. 
Form 20. 
United States Department of Agriculture, 
Office of Public Roads and Rural Engineering. 
Washington. D. C. 
Report on sample No of road material from 
ALade at the request of 
Material 
DETERMINATIONS . 
Specific gravity 
Weight per cubic foot pounds. 
Water absorbed per cubic foot pounds. 
Per cent of wear 
French coefficient of wear 
Hardness 
Toughness 
Cementing value 
Remarks 
Respectfully, 
— . Assistant Director. 
APPENDIX B. 
EQUIPMENT OF A ROAD-MATERIAL TESTING LABORATORY. 
A complete list of all apparatus necessary to carry on the work of 
rock testing follows : 
1 Deval abrasion machine having four cylinders. 
1 impact machine for toughness test 
1 Dorry machine for hardness test. 
1 impact machine for cementing- value test. 
1 cementing- value briquerte-forming machine. 
2 ball mills. 
1 diamond core drill, with suitable drill press. 
1 diamond saw. 
1 grinding lap. 
5 pounds Xo. 120 carborundum. 
1 small jaw crusher. 
1 scale, capacity 5 kilograms and sensitive to 0.5 gram. 
1 scale, capacity 100 grams and sensitive to 0.1 gram. 
1 balance, capacity 100 grams and sensitive to 0.01 gram. 
1 large drying oven. 
1 small drying oven, with temperature-regulating device. 
1 10-inch desiccator, with calcium chloride. 
1 millimeter scale. 
1 dozen pint jars with metal screw caps. 
1 dozen 3-quart enameled iron pans. 
1 100 c. c. graduate. 
1 100 c. c. beaker. 
1 15-inch standard sieve, with 30 meshes per linear inch. 
1 15-inch standard sieve, with 40 meshes per linear inch. 
1 16-inch sieve, reinforced with square openings one-sixteenth of an inch in size. 
