TABLE OF CONTENTS 



Evaporation. Temperature: Influence of latitude Altitude 

 Aspect Colour Capacity for heat Eadiation Conduction . 

 Miscellaneous properties : Colour Odour Tenacity Contraction 

 Diffusion. Mechanical analysis j>. .00 



CHAPTER IV. 



CHEMISTHY OF SOILS. 



Chemical analysis : Soil water Absorption Organic matter Lime 

 Insoluble mineral residue Total acid extract Available plant 

 foods. Chemical changes: Decomposition of minerals Oxi- 

 dation and reduction Dehydration Other reactions Soil 

 gases . . . , p. 96 



CHAPTER Y. 



BIOLOGY OF SOILS. 



The organisms. Algse. Moulds. Bacteria Reproduction Appear- 

 ance Food Antiseptics Sterilisation Chemical changes 

 Fixation of free nitrogen Hellriegel's discovery Sand cultures 

 Seat of fixation Inoculation of soils Fixation by non- 

 leguminous plants. Destruction of organic matter : Decay and 

 putrefaction Composts. Nitrification : Nature of change Pro- 

 duction of ammonia Nitrous and nitric ferments Simultaneous 

 action Habitat and conditions of growth Rate of nitrification 

 Denitrification Practical importance . . . . jt. 137 



CHAPTER VI. 



FERTILITY. 



Natural productiveness. Effects of removing crops. Maintenance of 

 fertility : Fallow Lay Restitution Quantity of available plant 

 foods required by crops Loss. Addition : Essential difference 

 between farmyard manure arid fertilisers. Conservation of 

 matter .......... p. 163 



