( 59 ) 

 Below is their analysis by Girardin and Bi- 

 dards : 



Soluble organic matter, 2.7 



Insoluble Humus, 49.8 



Sulphate of proto and per oxides of iron, 1.8 

 Fine sand, 39.0 



Sulphuret and per oxide of iron, 6.7 



CHAPTER Vlir. 



ECOBUAGE. 



Ecobuage is the process of burning the or- 

 ganic matters of a soil upon their own locality, 

 especially when they are poor in nitrogenous 

 principles. This operation transforms the 

 surface of the soil into a porous and carbona- 

 ceous earth, which condenses and retains the 

 ammoniacal vapours disengaged during com- 

 bustion ; it moreover produces alkaline and 

 earthy salts which are indispensable to vege- 

 tation. A too perfect combustion will, as in 

 the preparation of pyritous ashes, cause the 

 dissipation of the organic principles, and con- 

 sequently the manure ceases to be nitrogenous. 

 In America they practise Ecobuage by 

 setting fire to the fields when the grass is 

 dry enough for ignition. Some days after the 



