202 IRRIGATION. 



have disappeared ; this is the only fact which con- 

 cerns the farmer. The oxygen has heen absorbed 

 by natural waters, and 2-3 retained. What has be- 

 come of it ? It has gone, it is-not said all of it, but 

 in irrigation a large portion, to convert insoluble into 

 soluble geine. Irrigation is chiefly employed on grass 

 lands. The green sward here may not be broken 

 up — what if it was ? What if, by ploughing, it 

 was exposed to the action of the air? Remember 

 the properties of geine. Air converts the insoluble 

 to soluble, by forming carbonic acid, that is, the air 

 combines with the carbon of the geine, and forms that 

 gas. Give the geine this oxygen, condensed in wa- 

 ter : wet it with this concentrated oxygen, crowd it 

 into geine, as would be done by overflowing a meadow 

 with water. It penetrates every crack and cranny, 

 and every mole's-eye hole ; it expels the carbonic 

 acid imprisoned under the sod. It is doing the same 

 work upon the untouched green sward, which would 

 be effected by ploughing and tillage. The long and 

 the short of the whole action of irrigation with pure 

 limpid water is, that its absorbed oxygen, converts 

 insoluble to soluble geine. Is this explanation which 

 science offers, confirmed by practice ? The appeal 

 is made to all who have attended either to the the- 

 ory or practice of irrigation, to bear witness to its 



