MR WITHERS. 



207 



and the presence of oleaginous resin, render pine tim- 

 ber, when old and small grbwthed, not so brittle, nor 

 so liable to decay, as that of deciduous trees ; but it 

 becomes very deficient in lateral adhesion. From the 

 same cause we find the external layers of matured 

 pine timber comparatively superior to the quality of 

 the inner layers : in hard wood the exterior layers 

 are generally much inferior to the inner. Boards of 

 sap-wood of fast grown Scots fir, particularly of the 

 outside layers are much better suited — stronger and 

 more lasting, for boxes used as carriage packages, 

 or for machinery or cart lining much exposed to 

 blows and friction ; than boards of the best matured 

 red wood of Memel, Swedish, or Norway pine. This 

 is principally owing to the fast grown alburnum 

 possessing much greater lateral adhesion than the 

 matured wood of old pines. To have these sap- 

 wood boards in greatest perfection, the tree must 



steady, or that insect depredations or blights occur ; and a reserve 

 of food ought always to be retained. By careful inspection of 

 the nature of the annual wood deposit, or of the locality with re- 

 gard to moisture, it may be ascertained;, whether the irregularity 

 has been owing to difference of temperature, or of moisture, lu 

 warm climates the irregularity will generally depend on drought 

 and moisture, and in cold climates on heat and cold ; though 

 sometimes the depredations of insects, such as locusts, or of 

 blights, may be the cause. 



I 



