VIIl HOW CROPS FEED. 
CHAPTER Il. 
ORIGIN AND FORMATION OF SOILS.........0. ccc ccueeeneeeee gael nes townie 106 
§ 1. Chemical Elements of Rocks....... ........ cece ec ce eee eee n seen eceeenes 107 
§ 2. Mineralogical Elements of Rocks ......... siedde Hameed VeeKeneas taeee eee 108 
§ 8. Rocks, their Kinds and Characters. .........-.....+ stay sraveteielebeateis Si6 eeng ll Z 
§ 4. Conversion of Rocks into Soil .......... ed ota Staia aie’ eieeiaye~ 2e Weta evarasats ai Bivne tacos 122 
§ 5. Incorporation of Organic Matter with the Soil, and its Effects........... 185 
CHAPTER III. 
Kinps or Soins, THEIR DEFINITION AND CLASSIFICATION. 
TION 6:03 sieaisielsa sprees enineloniwisine suiedatewadeaas steele Seamusie es one LSB 
§ 2, Distinctions of Soils based upon Obvious or External Characters........ 146 
« 
CHAPTER IV. 
PaysicaAL CHARACTERS OF THE SOML...........04 ceceecccereceecenv coer ceeneLOT 
§ 1. Weight of Soils............. arb biiaeera tei cecaie -b8 is siewvanomsan oes: sinieniaisare lS 
§ 2. State of Division............ eizerwtabesaeaducreie ad aieshee a-sidiaieiatecessie LO, 
§ 8. Absorption of Vapor of Water..... acagetantentea ijeaceces aiteter aie braraNb CS FoleeSiatoscexerein 161 
§ 4. Condensation of Gases...........04 seeeeee Biasis'h aise Ajsateayiaays eiescumietosls 165 
§ 5. Power of Removing Solid Matters from Solution............ aspect Pee LTE 
§ 6. Permeability to Liquid Water. Imbibition. Capillary Power........... 1%6 
§ %. Changes of Bulk by Drying and Frost.............cececeeeeeee sae wee es 183 
§ 8. Adhesiveness....... 
§ 9. Relations to Heat... 
' CHAPTER V. 
Tur Som as a SouRcE or Foop To Crops: INGREDIENTS WHOSE ELEMENTS 
: ARE OF ATMOSPHERIC ORIGIN. 
§ 1. The Free Waiter of the Soil in its Relations to Vegetable Nutrition......199 
§ 2. The Air of the Soil... ............ 0... 00s sila avi Siete avctata Senne) ud 
§ 8. Non-nitrogenous Organic Matters. Humus..... saudariaciwtnete abeididistuineceteatere 222 
§ 4. The Ammonia of the Soil. ........... GiSiaidlaswieis db macmadine e seewnabusemie viele . 238 
§ 5. Nitric Acid (Nitrates) of the Soil 
§ 6. Nitrogenous Organic Matters of the Soil. Available Nitrogen... 
§ %. Decay of Organic Matters.... .......0.. esse eee neee shane Bake eile aise 
§ 8. Nitrogenous Principles of Urine 
§ 9. Comparative Nutritive Value of Ammonia-Salts and Nitrates...,........300 
221 
