32 THE PRINCIPAL SPECIES OF WOOD. 



English Oak. Quercus robur var. pedunculala. 



Nomenclature. 



English Oak. British Oak. Common Oan. 



Locality. 



Widespread throughout northern and central Europe. 



Features of Tree. 



Seventy to one hundred feet in height, three to five feet in 

 diameter. Crooked branches, stalkless leaves, long-stalked 

 acorns. 



Color, Appearance, or Grain of Wood. 



Heartwood light brown, darker spots frequent, sapwood 

 lighter. Compact structure. 



Structural Qualities of Wood. 



Hard, tough, strong, durable, difficult to work, liable to warp 

 in seasoning. 



Representative Uses of Wood. 



Ship-building, beams, cabinet-work, formerly carpentry. 



Weight of Seasoned Wood in Pounds per Cubic Foot. 

 51 (Laslett). 



Modulus of Elasticity. 

 1,170,000 (Thurston). 



Modulus of Rupture. 

 10,000 (Thurston). 



Remarks. 



The English, Chestnut, Durmast, or Red Oak, Q. robur var. 

 sessiliflora, distinguished by long leaf stalks and short acorn 

 stalks, affords practically similar but lower-rated wood. The two 

 varieties supply the British Oak of commerce. Dantzic, Rigi, 

 and some other European oaks take names from port of ship- 

 ment. Rubrus is red, but robur is a noun meaning strength ; 

 the adjective robustus means " oaken " or vigorous. Durmast 

 Oak, which is the Quercus pubescens of some botanists, is less 

 common than Quercus var. pedunculata. The two woods are 

 often confused. Laslett states that it is difficult to distinguish 

 one wood from the other without tracing logs back to original 

 sources. Early writers advised against the use of iron fasten- 

 ings with oak, but woods are now better seasoned, and, as 

 stated (see page 17), later practise does not support this view. 

 at least as applied to American woods.* 



* To determine the effect of gallic acid on iron : Five grams of clean iron wire 

 were immersed in a five per cent, solution of gallic acid. In nine days the weight 

 was 4,720 grams and the solution intensely black. Thirteen days later the same 

 specimen weighed 4-7453- This indicated the formation of a crust weighing more 

 than the original iron and probably protecting it to some extent 



