50 THE OLIVE 



ing, the flowers foil off and the tree gives its strength to wood. 

 The hygroscopicity of a soil, or the property of retaining moist- 

 ure, is of 2:reat vahie in a hot and drv countrv. It is well known 

 that the more a soil is manured and cultivated, the more moisture 

 it retains. The following table ^vill show the percentage of water 

 contained in different soils. 



Water contained 



in 100 parts 



of earth 



Silicious sand 25 



Gy^^sum 27 



Calcareous sand 29 



Drv chalk 40 



Chalk, soniewhut more fertile 50 



Clav soil 60 



Clay, pure 70 



Calcareous soil 85 



Manure 1.90 



Garden soil 89 



Arable land ; 52 



The capacity to absorb humidity from the atmosphere varies with 

 different soils. The following are the results of experiments. 



Absorbs in 24 hours. 



Silicious sand of water 



a 



Calcareous sand 1.5 '' 



Gypsum : 0.5 '' 



Drv chalk 13.0 ' 



Clialkv earth 15.0 



Clavev earth 18.0 " 



Clav 21.0 



Fine calcareuos earth 15.5 "' " 



Magnesia 38.0 " " 



Manure 48.5 " " 



Garden earth 22.5 " " 



Ordinarv earth 11.0 " " 



,i 



a a 



a a 



