COMPOSITION OF VARIOUS TREES 147 



the Confessor in Westminster Abbey is of oak, 

 and must be eight hundred years old. The oak 

 roof in Westminster Hall was built in the 

 reign of Richard II. ; and numerous other ex- 

 amples might be cited of the durability of the 

 timber of Quercus Rohur. 



The most suitable soUs for the oak are clayey, 

 gravelly, sandy and ironstone or reclaimed boggy 

 ground. 



The ashes of the oak contain in 100 parts : — 



One ton of oak extracts 41 lbs. of mineral 

 matter from the soil. 



The bark contains tannin, which is used in the 

 preparation of leather, and the acorn-cups of 

 Quercus JEgilops also contain tannin. Cork is a 

 product of Quercus Sober. 



L 2 



