50 BULLETIN 555, U. S. DEPARTMENT OF AGRICULTURE. 
When impracticable to follow the above method it is recommended that 
samples be taken from the storage tank at three different levels. 
Material in barrels or drums at a plant should be sampled by taking samples 
from not less than 3 per cent of the containers. 
Whenever possible, the portion of the sample from each drum or barrel 
should be taken from near the heart of the barrel after it has been split open. 
Where samples must be taken from the top of the barrel, the material lying 
within three inches of the surface should not be included. A hatchet or any 
sharp-pointed tool is suitable for the purpose of digging into the barrel. 
(Important. — Do not use kerosene on the blade.) The several portions are 
then to be pressed in a can of not less than one-quart capacity, using enough 
material very nearly to fill the can which is then tightly covered. If cans are 
not available and some other type of container used, they must be entirely free 
from paper or any other substance to which the bituminous material adheres 
readily. 
Check field samples are recommended on plant inspected material. 
Field sampling. — For barrel shipments, see plant barrel sampling. 
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 a 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. 1 — 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 least 1 square foot. 
The material should be carefully boxed in order that it may remain intact 
during transit. 
Sampling Portland Cement. 
Each shipment or lot of cement used on the work shall be sampled and 
tested in accordance with the standard specifications and tests for Portland 
cement given in the 1916 standards of the A. S. T. M. serial designation C9-17. 
It is recommended that in sampling cars and bins the method specified in 
A. S. T. M. 1916 standard specifications for Portland cement, section 17 (&) 
1 The term " bituminous aggregate " is defined as follows : The mineral or other aggre- 
gate, together with the bitumen which is used as the cementing medium. 
