CONTENTS 



INTRODUCTORY 



PAGE 



In the Scientific Study of Soils, Chemical, Physical, and Bio- 

 logical Considerations are involved . . • I 



CHAPTER I 



THE ORIGIN OF SOILS 



Sedentary Soils, and Soils of Transport — Weathering — 

 The Composition of Rock-forming Minerals and their 

 Weathered Products — Distinction between Soil and Sub- 

 Soil — General Classification of Soils • . .6 



CHAPTER n 



THE MECHANICAL ANALYSIS OF SOILS 



Nature of Soil Constituents : Sand, Clay, Chalk, and 

 Humus — Methods of Sampling Soils — Methods for 

 the Mechanical Analysis of a Soil — Interpretation of 

 Results ....... 32 



CHAPTER in 



THE TEXTURE OF THE SOIL 



Meaning of Texture and Conditions by which it is affected 

 — Pore Space and Density of Soils — Capacity of the Soil 

 for Water — Surface Tension and Capillarity — Percola- 

 tion and Drainage — Hygroscopic Moisture . . 60 

 xi 



