10 
BULLETIN" &49, U. S. DEPARTMENT OF AGRICULTURE. 
(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- 
k, 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 
g r = Weight of material (g) 
V' ° Displaced volume (c. c.) 
(b) 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. 
Fig. 
have two 01 cc 
Graduations e.rtend 
above 1 and 
befow OMarft-- 
Capacif-y 
of Bulk 
approx 
2S0cc 
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 
Chatelier apparatus for specific-gravity deter- 
minations. 
