OAK. 



(Quercus.) 



The oaks are found on all of the continents of the northern 

 hemisphere, as well as at high altitudes just south of the 

 equator. Their woods stand pre-eminent among those of the 

 broadleaf series and have been highly prized from early 

 periods. Formerly relied upon for all purposes of house and 

 naval architecture, they did not give way to the so-called 

 " soft woods " for houses, and to iron for vessels, until com- 

 paratively recent periods. They were supplanted for the 

 former purposes upon the opening of the soft-wood forests of 

 North America and of the Baltic, and for vessels subsequent 

 to the conclusions of the American Civil War. 



The historical importance of oak is founded upon the repu- 

 tation of the English Oak as derived from two trees, Quercus 

 robur var. pedunculata and Quercus robur var. sessiliflora, 

 usually taken as sub-species of Quercus robur.* It is said that 

 these trees once formed large forests over Northern and 

 Central Europe. Live-oak has always been highly esteemed, 

 but is now very scarce. It is one of the hardest, heaviest, 

 and most durable of constructive woods and was once largely 

 employed in ship-building. The wood of the White Oak 

 (Quercus alba] is at present preferred for most purposes foi 

 which oak is now employed, and is one of the most valuable 

 of the American hard woods. 



Oak is tough, durable, easily obtained, liable to warp and 

 check in seasoning, often hard to nail without splitting, sus- 

 ceptible of high polish, and not greatly liable to attack by 

 insects. It contains gallic acid, causing peculiar taste and odor 

 and attacking iron, the solutions staining the wood. Experi- 

 ments t indicate that iron fastenings are shortly protected by 

 an insoluble scale of resulting salt, and that the wood, although 



* Thought by some botanists to be distinct species, namely, Quercus pedun- 

 culata and Quercus sessiliflora. 



f Havemeyer Chemical Laboratory, N. Y. University. II 



