ARTIFICIAL MIXTURES 143 



or nitrate of lime and the mixture allowed to stand 

 overnight. Nitric acid is liberated in the free condition. 

 The reaction is hastened and made more evident by the 

 action of heat. 



(J?) Superphosphate and Kainit or Muriate of Potash. 

 — The experiment {a) is repeated with kainit or muriate 

 .of potash instead of nitrate. After some time hydro- 

 chloric acid is liberated as a gas, and may be detected 

 by holding a piece of blue litmus paper over the 

 mixture. 



{c) Lime and Aminoniacal Compounds. — Sulphate 

 of ammonia, guano, or other fertilisers containing 

 ammonium salts when mixed with lime and slightly 

 moistened quickly give off free ammonia. The reaction 

 is hastened by gentle heating. 



{d) Basic Slag and Ammoniacal Compounds. — Owing 

 to the free lime which it contains, basic slag acts as in 

 (^), with the liberation of ammonia from ammonium 

 salts, etc. This can be shown in the same way. 



{e) Basic Slag and Nitrates. — Although without 

 action on each other it is inadvisable to make a 

 mixture of these two manures, owing to the high 

 density of the slag, which prevents proper mixing. 



Equal parts of basic slag and nitrate are mixed 

 together and shaken in a closed tube for some time. 

 The slag gradually accumulates at the bottom of the 

 tube. 



136. Analysis of Mixed Manures. 



(a) Sampling. — The sample must be disintegrated 

 as far as possible, pieces of stone, etc., removed and 

 their weight determined, and the residue thoroughly 

 mixed and a sufficient portion withdrawn and ground 

 to a powder. 



{b) General Analysis. — Moisture, nitrogen, nitrates 



