38 



WOOD AND FOREST. 



the trunk itself close tigiiter and tighter around it, until it is broken 

 off. Then, unless it has begun to decay, it is successivel)- overgrown 

 b]' annual layers, so that no sign of it appears until the trunk is cut 

 open. A lai-ge trunk perfectly clean of branches on the outside may 

 have many knots around its center, remnants of branches which grew 

 there in its .youth, as in Fig. 34, and Fig. 8, p. 18. The general ef- 



Fig. 32- Fit.rure Fornieii b\- Pilli Ra\s 

 ill Oak (full size). 



FiL^ 33. Swofl Gum, Shdwiiig- Uneven 

 Deposit (if Coloring Matter (fuU size.) 



feet of the presence of a knot is, that the fihci's that grow ai-ound and 

 over it are bent, and this, of course, produces crooked grain. 



Following are the designations given to different knots by lumber- 

 men: A sound knot is one which is solid across its face and is as 

 hard as tlie wood surrounding it and fixed in position. A /))'() knot 

 is sound, but not over %" in diameter. A standard knot is sound 



