III.] THE CLASSIFICATION OF TIMBERS. 51 



weight in most cases. Woods are also even-grained, 

 or cross-grained, open, rough, &c., in various degrees. 



The colour of a timber is sometimes a useful cha- 

 racter, and has been already referred to when speaking 

 of the heart-wood and sap-wood, which usually have 

 different hues. 



There are a few other characteristics afforded by 

 special kinds of timber which should be noticed, 

 though they cannot be made use of in a general 

 classification. I refer particularly to such peculiari- 

 ties as the odours of sandal-wood, deal, teak, toon, 

 and the Australian pencil-cedar {Synotmi glandtt- 

 losum\ &c. Certain special markings, such as the 

 satiny lustre of satin-wood ; the white mineral 

 substances (apatite I) in the vessels of teak ; the 

 appearance of the polished surface, and a number 

 of other features which come under the notice of the 

 timber merchant and technologist must be passed 

 over here, useful as they are for the recognition of 

 special timbers on the spot. 



A high authority has written, with respect to this 

 subject, " It is not always easy to give in words an 

 explanation of the reasons which lead one who is 

 tolerably conversant with the structure of woods to 

 pronounce an opinion ; there are often characters of 

 appearance, touch, colour, odour, &c., which afford 



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