56 BULLETIN 6&1, U. S. DEPAETMENT OF AGRICULTURE. 



IV. TESTING. 



8. 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 refiected 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. (| inch) from the side of the container and not less than 1 

 cm. (I 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. 



(6) 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-4 in 1917.] 



1. Sampling. — The .sample as received shall be thoi'oughly 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. Appar-atus. — 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. 



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. 



Diameter of tubulature cm. 0.9 



Angle of tubulature ^ deg. 75 



A variation of 3 per cent from the above measurements will be allowed. 



