fertilising ingredients in soils 90
Value of chemical analysis of soils 90
III. Biological properties of a soil 92
Bacteria of the soil 92
Recapitulation of Chapter I 96

APPENDIX TO CHAPTER I.
NOTE
I. Table of absorptive power of soil substances by Schuebler 98
II. Table of rate of evaporation of water in different soils
by Schuebler 99
III. Table of hygroscopic power of soils dried at 212 deg. F.
(Davy) 99
IV. Gases present in soil 100
V. Amount of plant-food in soils 100
VI. Chemical composition of the soil 101
VII. Forms in which plant-foods are present in the soil 107

CHAPTER II.--FUNCTIONS PERFORMED BY MANURES.

Etymological meaning of word manure 109
Definition of manures 110
Different classes of manures 111
Action of different classes of manures 113

CHAPTER III.--POSITION OF NITROGEN IN AGRICULTURE.

The Rothamsted experiments and the nitrogen question 115
Different forms in which nitrogen exists in nature 116
Relation of "free" nitrogen to the plant 117
Combined nitrogen in the air 118
Amount of combined nitrogen falling in the rain 119
Nitrogen in the soil 120
Nitrogen in the subsoil 121
Nitrogen of surface-soil 121
Amount of nitrogen in the soil 123
Soils richest in nitrogen 123
Nature of the nitrogen in the soil 124
Organic nitrogen in the soil 125
Differences of surface and subsoil nitrogen 126
Nitrogen as ammonia in soils