60 BULLETIN 691, U, S. DEPARTMENT OP AGRICULTURE. 



through the discharge pipe for a sliort time before the sample is taken and the 

 drip valve should be so regulated that the operation of collecting the sample 

 continues through the entire period of loading the containers. 



SAMPLING FROM STORAGE TANKS AND TANK CARS. 



(1) When the material is in a fluid condition three samples should be taken 

 from each tank or tank car, one from the top, one from the bottom, and one from 

 the center of the tank. The bottom sample may be taken from the discharge 

 pipe through which a suflicient amount of the material is firs.t allowed to flow 

 so as to clean it properly. If there is no outlet at the middle of the tank a 

 thief sample may be taken by lowering a closed bottle or can to the center of 

 the tank and then removing the stopper or cover by means of a stout cord or 

 wire to which it is attached. (2) Tank cars containing cold semisolid or solid 

 bituminous material may be sampled through the dome by the use of a 

 clean hot shovel. 



SAMPLING FROM BARRELS AND DRUMS. 



(1) Separate samples should be taken from not less than 3 per cent of the 

 containers. (2) When the material is semisolid or solid samples should be 

 taken at least 3 inches below the surface. A hatchet may be used if the 

 material is hard and a broad stiff putty knife if the material is soft. 



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