56 BULLETIN 691, U. S. DEPARTMENT OF AGRICULTURE. 
IY. TESTING. 
S. Testing. — (a) In making the test the sample shall be placed in the trans- 
fer dish filled with water from the water bath of sufficient depth to completely 
cover the container. The transfer dish containing the sample shall then be 
placed upon the stand of the penetration machine. The needle, loaded with 
specified weight, shall be adjusted to make contact with the surface of the 
sample. This may be accomplished by making contact of the actual needle 
point with its image reflected by the surface of the sample from a properly 
placed source of light. Either the reading of the dial shall then be noted or 
the needle brought to zero. The needle is then released for the specified period 
of time, after which the penetration machine is adjusted to measure the dis- 
tance penetrated. 
At least three tests shall be made at points on the surface of the sample not 
less than 1 cm. (f inch) from the side of the container and not less than 1 
cm. (| inch) part. After each test the sample and transfer dish shall be 
returned to the water bath and the needle shall be carefully wiped toward its 
point with a clean, dry cloth to remove all adhering bitumen. The reported 
penetration shall be the average of at least three tests whose values shall not 
differ more than four points between maximum and minimum. 
(5) When desirable to vary the temperature, time and weight and. in order 
to provide for a uniform method of reporting results when variations are 
made, the samples shall be melted and cooled in air as above directed. They 
shall then be immersed in water or brine, as the case may require, for one hour 
at the temperature desired. The following combinations are suggested : 
At 0° C. (32° F.) 200-g. weight, 60 seconds. 
At 46.1° C. (115° F.) 50-g. weight, 5 seconds. 
DISTILLATION TEST. 
[A. S. T. M. Standard Test D20-16. With tentative revision in thermometer require- 
ments recommended by committee D— ± in 1917.] 
1. Sampling. — The sample as received shall be thoroughly stirred and agi- 
tated, warming, if necessary, to insure a complete mixture before the portion 
for analysis is removed. 
2. Dehydration. — If the presence of water is suspected or known, the mate- 
rial shall be dehydrated before distillation. About 500 cc. of the material are 
placed in an 800-cc. 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-cc. 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. Apparatus. — The apparatus shall consist of the following standard parts: 
(a) Flask: The distillation flask shall be a 250-cc. Engler distilling flask, 
having the following dimensions : 
Diameter of bulb cm... 8.0 
Length of neck cm.__ 15. 
Diameter of neck cm.__ 1. 7 
Surface of material to lower side of tubulature cm.__ 11. 
Length of tubulature cm. 15.0 
Diameter of tubulature cm. 0.9 
Angle of tubulature deg. 75 
A variation of 3 per cent from the above measurements will be allowed. 
