EXAMINATION OF BITUMINOUS EOAD MATERIALS. 



17 



testing flame. The testing flame is obtained from a jet of gas 

 passed through the piece of glass tubing and should be about 5 milli- 

 meters in length. 



The flash test is made as follows: The oil cup should first be 

 removed and the bath filled with cottonseed oil. The oil cup should 

 be replaced and filled with the material to be tested to within 3 

 millimeters of the flange joining the 

 cup and the vapor chamber above. 

 The glass cover is then placed on the oil 

 cup and the thermometer so adjusted 

 that its bulb is just covered by the bi- 

 tuminous material. The Bunsen flame 

 should be applied in such a manner that 

 the temperature of the material in the 

 cup is raised at the rate of about 5° 

 C. per minute. From time to time 

 the testing flame is inserted in the 

 opening in the cover to about half 

 way between the surface of the ma- 

 terial and the cover. The appearance 

 of a faint bluish flame over the entire 

 surface of the bitumen shows that the 

 flash point has been reached and the 

 temperature at this point is taken. 



The burning point of the material 

 may now be obtained by removing the 

 glass cover and replacing the thermom- 

 eter in a wire frame. The tempera- 

 ture is raised at the same rate and the 

 material tested as before. The tem- 

 perature at which the material ignites 

 and burns is taken as the burning point. 



At the conclusion of this tost the 

 flame should not be blown out for dan- 

 ger of splashing the hot material. A mel al cover or extinguisher should 

 be employed for this purpose by placing it over the, ignited material. 



e- 



.-C 



Fin. 9.— New York State Board o Health 

 oil tester. 



OPEN-CI I» METHOD. 



A [lumber of open-cup oil te, ters have, been devised which are 



similar in design and give practically equivalent results. This typo 



flOWn in figure If). It consists of a bmss oil cup <i of about LOO 



cubic centimeters capacity. The outer vessel U serves as an air 



• i. No glass cover is used i> ( the opon-cup method. A suitable 



116° Hull. 314 -15 .'} 



