CHAPTER II. 

 THE RECOGNITION AND CLASSIFICATION OF WOODS. 



NOT only carpenters and other workers in wood, but engineers, 

 surveyors and timber-merchants at present recognize the timbers 

 with which they are familiar as to kind, and even largely as to 

 quality, by methods obviously and confessedly empirical, mere 

 "rule of thumb." From this it results that, though woods may 

 be accurately discriminated generically, as oak, ash, birch or 

 pine, the species are seldom correctly distinguished, and, as a 

 consequence, the best wood for any particular purpose is very 

 often not obtained. 



In these empirical identifications such nrore obvious but 

 variable, and therefore less trustworthy, characters as weight, 

 hardness, colour and odour are often more used than most of 

 the structural characters described in the previous chapter. In 

 attempting a more thoroughgoing discrimination we cannot 

 ignore these more obvious characters ; but it is important to 

 recognize their variability and consequently merely secondary 

 importance. Details as to the testing of weight and hardness 

 will form the subject-matter of a subsequent chapter : we are 

 here only concerned with rough approximations. 



Weight of wood. The weight of wood depends mainly 

 upon two things, its compactness and its moisture. Compactness 

 signifies the amount of woody or other solid matter in a given 

 bulk, and this will generally be greater in slow-growing than in 



