VI METHODS OF ANALYSIS. 



II. Methods for the analysis of soils Continued. Page. 



11. Carbon dioxid 19 



12. Humus 19 



13. Humus nitrogen 19 



14. Soil acidity 20 



15. Statement of results 20 



III. Methods for the analysis of inorganic plant constituents 21 



1. Preparation of sample 21 



2. Carbon-free ash 21 



(a) Preparation of standard calcium acetate 21 



(b) Preparation of ash 21 



(c) Carbon dioxid 21 



(d) Carbon, sand, and silica 22 



3. Manganese, calcium, and magnesium 22 



4. Phosphoric acid 22 



5. Sulphuric acid, sodium, and potassium 23 



6. Chlorin 23 



Volhard method of determining chlorin 23 



(a) Solutions required 23 



(b) Determination 23 



7. Potassium in plants 23 



8. Sulphur in plants peroxid method 23 



9. Chlorin in plants 24 



IV. Methods for the analysis of insecticides and fungicides 25 



1. General directions 25 



2. Paris green 25 



(a) Moisture 25 



(b) Total arsenious oxid, method I (Smith) 25 



(c) Total arsenious oxid, method II (Avery) ; . 26 



(d) Total arsenious oxid, method III (Avery-Haywood) 26 



(e) Sodium-acetate-soluble arsenious oxid 27 



(f) Water-soluble arsenious oxid 27 



(g) Total copper oxid, method I (electrolytic) 27 



(h) Total copper oxid, method II (thiosulphate) 27 



3. London purple 28 



(a) Moisture 28 



(b) Total arsenious oxid, method I (Haywood) 28 



(c) Total arsenic oxid, method I (Haywood) 28 



(d) Total arsenious oxid, method II (Haywood-Davidson) 29 



(e) Total arsenic oxid, method II (Haywood-Davidson) 29 



(f) Water-soluble arsenious oxid 29 



(g) Water-soluble arsenic oxid 30 



4. Copper carbonate 30 



(a) Copper oxid 30 



5. Potassium cyanid 30 



(a) Cyanogen 



6. Soap 



(a) General statement 



(b) Moisture 



(c) Total alkali 31 



7. Soda lye 



(a) Carbonate and hydroxid, method I 



(b) Carbonate and hydroxid, method II (Cameron) 32 



