74 BULLETIN 949, U. S. DEPARTMENT OF AGRICULTURE. 



Sampling fluid products. — When a fluid material is shipped in tank cars, and the 

 sample is to be taken directly from the tank car to represent an average of the entire 

 tank-car contents, the following method is suggested : 



A tin can. with a tight-fitting removable cover and wire handle, is secured, and a 

 number of holes one-eighth of an inch in diameter are punched in the cover. This 

 bucket is then weighted in any convenient way and lowered slowly by means of a 

 cord attached to the handle through the entire depth of the tank car, so that the 

 can will be filled with material from all depths of the car. This can is then emptied 

 into another can of at least 1 quart capacity having a screw top or other equally tight 

 cap or cover. A sample is more representative when the tank car has been agitated 

 before the sample is taken. 



Where individual samples are desired to check the uniformity of material throughout 

 a tank car, it is suggested that thief samples be taken from top and middle and a 

 third sample be taken from the outlet valve through which a sufficient amount of 

 bituminous material has been allowed to flow in order to clean the valve properly. 



Semisolid products. — Barrel shipments are to be sampled as in plant sampling. 



Tank-car shipments are to be sampled through the dome by the use of a clean hot 

 shovel. 



Bituminous aggregates. 15 — It is suggested that a 5-pound sample be submitted when 

 the material is sampled before being placed in the pavement. 



Samples of pavements should be at le ast 1 square foot in area. 



The material should be carefully boxed in order that it may remain intact during 

 transit. 



59. SAMPLING PORTLAND CEMENT. 



See test No. 17. 

 See test No. 18. 



60. SAMPLING PAVING BRICK. 



61. SAMPLING METAL CULVERTS. 



Owing to lack of uniformity of spelter coating on culvert sheets, it is recommended 

 that as many samples as possible be taken from different culverts, each sample to be 

 about 3 inches square. 



The samples should be straightened preferably in a press or vise — under no circum- 

 stances should they be hammered. 



62. SAMPLING OF PAINT AND PAINT MATERIALS. 



Where a shipment of such material consists of a number of separate packages a 

 sample should be taken from a sufficient number of such packages to give a repre- 

 sentative composite sample. The contents of the containers should be stirred to 

 homogeneous consistency before sampling. 



In case of mixed paints, oils, and thinners the sample should be at least a pint. 

 Preferably the sample should be placed in an air-tight friction top can. In the case 

 of pastes and dried pigments the sample should be approximately 1 pound. 



is>The term "bituminous aggregate" is defined as follows: The mineral or other aggregate, together 

 with the bitumen which is used as the cementing medium. 



