Influence of tillage on number of plants in a certain area 86 Comparison of English and American farming 86 II. Chemical composition of a soil 87 Fertilising ingredients of a soil 87 Importance of _nitrogen, phosphoric acid_, and _potash_ in a soil 88 Chemical condition of fertilising ingredients in soils 89 Amount of soluble 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.