COMPOSITION OF VARIOUS TREES 95 



Birch wood yields on destructive distillation 

 oleum rusci or birch tar. Birch tar contains 

 guaiacol, cresol, and pyrocatechin, and it has 

 a peculiar odour which it imparts to Eussian 

 leather. 



Box Tree [Buxus sempervirens, Natural Order, 

 Euphorbiaceae) is a hardy evergreen shrub, valuable 

 for hedges. The dwarf box (B. suffruticosa) is 

 used for box edgings. It grows in ordinary soils. 



The ashes of the wood contain in 100 parts : — 



