THE OLIVE 



51 



Absorbtion is greater by night than by day. and recently cultiva- 

 ted ground is the most receptive, as it exposes the greater number 

 of particles to the action of the air. 



As the earth grows dry. its capacity to absorb moisture diminish- 

 es. So we observe that ground frequently and thoroughly cultiva- 

 ted retains moisture the longest. 



THE DRYING QUALITY OF SOILS. 



Of 100 parts 

 of water. 



Silicious sand in four hours evaporates 88.4 



Calcareous " " " " " 75.9 



Gypsum " " " " 71.7 



Dry chalk " " " " 52.0 



Earthy " " " " " 45.7 



Clayey soil « " " " 34.6 



Clay " " " " 31.9 



Carbonate of lime in four hours evaporates 28.9 



Manure " " " " 20.5 



Magnesia " " " " 10.8 



Garden earth " " " " 24.3 



Arable hand " " " 32.0 



These figures indicate what we see in practice, that the more 

 sandy the soil, the sooner it dries. Some soils when they dry, actu- 

 ally diminish in volume, and through splits and cracks expose the 

 roots of the tree. Sandy, limey and gypsum soils do not have this 

 drawback ; the others vary in the following degrees. 



Of 1000 parts. 



Carbonate of lime soils loses 50 



Dry chalk " " 60 



Earthy " " " 89 



Clayey soil " " 114 



Clay " " 183 



Magnesia " " 4 154 



Manure " " 200 



Garden earth " " 149 



Arable land " " 95 



