10 



BULLETIN 949, U. S. DEPARTMENT OF AGRICULTURE. 



Ground Glass 

 Stopper 



Sp.grav.= 



(3) (a) The flask shall be filled with either of the liquids to a point on the stem be- 

 tween zero and 1 c. c, and 64 grams of sand or other fine non-bituminous highway 

 material of the same temperature as the liquid shall be slowly introduced, taking care 

 that the material does not adhere to the inside of the flask above the liquid and to 

 free the material from air by rolling the flask in an inclined position. After all mate- 

 rial is introduced, the level of the 

 liquid will rise to some division of 



the graduated neck; the difference 



between readings is the volume 

 displaced by 64 grams of the ma- 

 terial. 



The specific gravity shall then 

 be obtained from the formula 



Weight of material (g) 

 Displaced volume (c. c.) 



(6) The flask, during the opera- 

 tion, shall be kept immersed in 

 water, in order to avoid variations 

 in the temperature of the liquid in 

 the flask, which shall not exceed 

 0.5° C. The results of repeated 

 tests should agree with 0.01. 



II. JACKSON TEST. 



(4) The determination shall be 

 made with a Jackson specific-grav- 

 ity apparatus (illustrated in fig. 9), 

 which shall consist of a burette, 

 with graduations reading to 0.01 in 

 specific gravity, about 23 cm. (9 

 inches) long and with an inside 

 diameter of about 0.6 cm. (0.25 

 inch), which shall be connected 

 with a glass bulb approximately 13 

 cm. (5.5 inches) long and 4.5 cm. 

 (1.75 inches) in diameter, the glass 

 bulb being of such size that from 

 a mark on the neck at the top to a 

 mark on the burette just below the 

 bulb, the capacity is exactly 180 

 c. c. (6.09 liquid ounces); and an 

 Erlenmeyer flask, which shall con- 

 tain a hollow ground-glass stopper 

 having the neck of the same bore 

 as the burette, and shall have a 

 capacity of exactly 200 c. c. (6.76 

 ounces) up to the graduation on the 

 neck of the stopper. 



(5) The method is as follows: (1) Dry at not more than 110° C. (230° F.) to a con- 

 stant weight a sample weighing about 55 grams; (2) weigh 50 grams of the dry sample 

 to 0.1 gram and pour it into the unstoppered Erlenmeyer flask, which shall be cleaned 

 and dried before each determination; (3) fill the bulb and burette with kerosene, 

 leaving just space enough to take the temperature by introducing a thermometer 



Have two Olcc 

 Graduations extend 

 above 1 and 



below OMarh--- 





~7T 



j_Y_>L_ 



Fig 



Chatelier apparatus for specific-gravity deter 

 ruinations. 



