THE WOOD 



221 



pattern or picture presented by the wood. This is best 

 seen in woods like oak, ash, and chestnut, where the pores 

 of the spring wood are so large that they need a " filler" 



FIG. 79. Wood of Spruce 



1, natural size ; 2, small part of one ring magnified 100 times. The vertical 

 tubes are wood fibers, in this case all "tracheids." HI, medullary or pith 

 ray; n, transverse tracheids of pith ray; a, b, and c, bordered pits of the 

 tracheids, more enlarged 



in finishing or polishing. The pores are the most impor- 

 tant marks by which we can distinguish woods, and we 

 divide all of our woods into three groups : 



