CONTENTS. 1x 
CHAPTER VI. 
THE Som as A SouRcE oF Foop ro Crops: INGREDIENTS WHOSE ELEMENTS 
ARE DERIVED FROM Rocks. 
§ 1. General View of the Constitution of the Soil as Related to Vegetable 
Nutrition ............. seraiare lara laterslaiargial la wieteiated eiewadeaialeele 5 Mean 305 
§ 2. Aqueous Solution of the Soil wo. ccs, cavnsaawanneuve enone veunesen pena vat 309 
§ 3. Solution of the Soil in Strong ACid8..........ccccece cece cece cee ceeeeeee 329 
§ 4. Portion of Soil Insoluble in Acids................ 2. assets eines asta 330 
§ 5. Reactions by which the Solubility of the Elements of the Soil fs al- 
tered. Solvent Effects of Various Substances. Absorptive and 
Fixing Power of Soils..... : 
§ 6. Review and Conclusion...... 
