168 § 96. ANALYSIS OF SOILS AND EOCKS. 



height of the locality above the level of the sea should 

 be noted also. 



d. The management and rotation of crops in previous 

 years. 



e. The character of the customary manuring. 



/. The amount of the crops removed in the preceding 

 year, and, if possible, the average amount of each of the 

 more important crops yielded by the field. 



g. The practical judgment of neighboring farmers in 

 regard to the field. 



Having taken the sample to the laboratory, separate 

 the stones and larger pebbles from the finer parts by the 

 hand, or by sifting with a very coarse sieve, and examine 

 them with reference to their mineralogical character, 

 weight and size, making note, in this last respect, of the 

 number that are as large as the fist or larger, the num- 

 ber as large as an ^^^^ a walnut, hazel-nut, and pea,, or 

 give the percentage of each by weight. 



Pulverize the air-dried soil in a mortar with a wooden 

 pestle, and separate the fine earth out by a sieve with 

 meshes 3 mm. wide ; this sieve should have a tightly fit- 

 ting cover of sheep-skin stretched over a hoop, and it 

 should be covered in the same manner underneath, so 

 that no dust can escape during the process of sifting. 



Wash the pebbles and vegetable fibres remaining on 

 the sieve with water, dry and weigh the residue, and ex- 

 amine the pebbles mineralogically ; the water with which 

 this gravel was washed should be evaporated to dryness 

 at a temperature not exceeding 50° C. towards the close 

 of the evaporation, and the residue mixed with what 

 passed through the dry sieve. 



This sifted fi^ie earth is reserved for all the processes 

 hereinafter described, and is kept in well-stoppered bot- 

 tles, marked air-dried fine earth. 



