15 



SAMPLING OF MATERIAL IX BAGS. 



In sampling material which is shipped in bags, portions should be 

 drawn from at least ten per cent of the number of bags present. A 

 fair sample may be obtained by emptying about ten per cent of the 

 bags present on a clean floor or other smooth surface and thoroughly 

 mixing : small amounts are then taken from different parts of the 

 heap and an average sample drawn as has been previously described. 



SAMPLING or SOILS. 



The correct taking of representative soil samples, when such are 

 desired for chemical investigation, is of the first importance, as with- 

 out a properly taken sample, the results which a careful chemical 

 analysis will show become of little value. The sample should be 

 taken from different portions of the field and to a depth not exceed- 

 ing the downward limit of the surface soil. After selecting a place 

 where a sample is to be taken, pull up all growing vegetation and 

 remove all surface matter which is not a part of the soil. Dig a hole 

 in the soil about two feet square, making the sides smooth and clean 

 by means of a sharp pointed shovel or other instrument ; now place 

 a sharp bladed shovel at the point of separation of the surface soil 

 from the subsoil and by means of another flat bladed instrument 

 shave off a portion (about two inches) from all four sides of the 

 aperture letting the soil fall into a shovel which is held in a proper 

 position to receive the same. Place the soil in a suitable receptacle 

 and proceed to take other samples in a like manner from several 

 different parts of the field. The large bulk of soil which has thus 

 been taken is now placed on a clean floor or on a large piece of thick 

 paper and thoroughly broken up and mixed, after which an average 

 sample is drawn and placed in a glass jar or bottle. The bottle is 

 then securely stoppered and sealed, properly labelled and forwarded 

 for the subsequent chemical examination. 



A description of the soil should accompany the sample or be sent 

 in a sealed letter, setting forth the locality, depth at which the 

 sample was taken, nature of subsoil and depth, the method of fertil- 

 ization and crop rotation which has been in practice, general fitness 

 of land for cultivation and all other information that would be of 

 interest or assistance to the chemist in formulating his report. 



Care should be exercised in sampling when the weather conditions 

 are normal and no time should be lost between the drawing of the 

 sample and the forwarding of same to the laboratory. This point 

 applies with equal force to all materials forwarded for investigation. 



