145-146] QUALITATIVE ANALYSIS 53 



SECTION IV 



QUALITATIVE ANALYSIS OF THE BODIES 

 COMMONLY OCCURRING IN SOILS AND MANURES 



Introductory Remarks 



145. This section treats only of those bodies which 

 occur in soils, manures, and agricultural products, namely, 

 the carbonates, sulphates, chlorides, nitrates, nitrites, sili- 

 cates, and phosphates of the metals aluminium, iron, manga- 

 nese, calcium, magnesium, potassium, sodium, and ammo- 

 nium, together with organic carbon, nitrogen, chlorine, and 

 sulphur. 



Chemical formulae are freely used, but not unless the 

 name of the compound has already been mentioned in the 

 same paragraph. 



In some instances the chemical changes are expressed 

 by equations. 



146. The systematic name of an inorganic compound 

 such as a salt is usually a double name, the metal forming 

 one portion, and the acid portion (called the acid-radical) 

 the other portion of the name. Thus sodium on being 

 added to sulphuric acid would form sodium sulphate : — 



Na 2 + H 2 S0 4 



Sodium Sulphuric 



acid 



Hence the names of both metal and acid, or some modifi- 

 cation of them, are included in the name of the compound 

 formed. In analysis it is found convenient to test for the 

 metal and the acid-radical separately. In the above case of 



