62 
BULLETIN 1216, U. S. DEPARTMENT OF AGRICULTURE. 
In Ailing, the material shall he poured in a thin stream hack and 
forth from end to end of the mold until it is more than level full, 
it shall then be left to cool in the air at a temperature not lower 
than 15.5° C. (60° F.), for 30 minutes, after which the excess of 
bitumen shall be cut off by means of a hot putty knife or spatula 
so that the mold shall be just level full. 
(i. The brass plate and mold, with briquet, shall then he placed 
in the water hath and kept at a temperature of 25" C (77° F.) 
for at least 1 \ hours, when the briquet shall he removed from the 
plate and the side pieces detached. 
7. The rings on the clips shall then be attached to the pins or 
hooks in the ductility machine and the two clips pulled apart at a 
uniform speed of 5 centimeters per minute (±5 per cent). While 
the test is being made the water In the tank of the ductility 
machine shall cover the sample by at least 25 centimeters and 
shall he kept continuously at a temperature within 0.5° C. of 
25° C. (77° F.). When the specimen of bituminous material 
breaks, the distance from the original position of the clip before 
pulling to its present position shall be measured, and shall he 
known as the ductility. The average of three tests shall he taken, 
excepting that any abnormal result shall be rejected. 
TEST FOR DISTILLATION OF BITUMINOUS MATERIALS 
SUITABLE FOR ROAD TREATMENT. 
(A. 
M. standard method, serial designation D 20-18, Blightly 
modified.) 
Flask. 
Thermometer. 
1. The sample as received shall he thoroughly stirred and agi- 
tated, warming, if necessary, to insure a complete mixture hefore 
the portion for analysis is removed. 
2. The distillation test shall he made on the sample as received, 
unless the Sample shows in the distillation test water in excess of 
3 per cent. In that case the sample shall be previously dehy- 
drated in accordance with the following method: About 500 cubic 
centimeters of the material are placed in an 800 cubic centimeter 
copper still provided with a distilling head connected with a 
water-cooled condenser. A ring burner is used, starting with a 
small flame at the top of the still and gradually lowering it. if 
necessary, until all the water has been driven off. The distillate 
is collected in a 200 cubic centimeter separatory funnel, with the 
tube cut off close to the Stopcock. When all the water has been 
driven over and the distillate has settled out, the water is drawn 
off and the oils returned to the residue in the still. The contents 
of the still shall have cooled to below 100° C. before the oils are 
returned, and they shall be well stirred and mixed with the 
residue. 
3. The apparatus shall consist of the following standard parts: 
(a) Flask. — The distillation flask shall be a 250 cubic centi- 
meter Engler distilling flask, having the following dimensions: 
Diameter of bulb: 8 centimeters. 
Length of neck: 15 centimeters. 
Diameter of neck: 1.7 centimeters. 
Surface of material to lower side of tubulature: 11 centi- 
meters. 
Length of tubulature: 1.". centimeters. 
Diameter of tubulature: <>.!> centimeter. 
Angle of tubulature: 75°. 
A variation of 3 per cent from the above measurements will be 
allowed. 
ih) Thermometer — The thermometer shall conform to the fol- 
lowing requirements : 
It shall be made of t hermomet ric glass of a quality equivalent 
to suitable grades of Jens or Corning make, it shall be thor- 
oughly annealed, it shall be filled above the mercury with inert 
gas which will not act chemically on or contaminate the mercury. 
