496 OF USEFUL AND BOOK T. 



take place in a considerable degree even if the stem of the cul- 

 tivated or quick growing one were thicker than that of the 

 other in the wild state. Supposing that we had no other proofs, 

 this clearly shews that cultivation, or whatever tends to increase 

 the growth of a tree, tends also to expand the vegetable fibre. 

 But there are other concurring proofs, which demonstrate this, 

 and at the same time shew, what few I suppose will doubt, that 

 when the vegetable fibre is expanded, or when the annual ring- 

 lets or circles of wood, produced by a tree, are soft and larger 

 than the general annual increase of such tree, the timber must 

 be less hard, and more permeable by air, water, heat, &c. 



2. It is well known, that the common oak in Italy, where it 

 grows faster than in Britain, is comparatively of short duration. 

 And that the oak which grows on the mountains, in the High- 

 lands of Scotland, is much harder and closer than any produced 

 in England ; though on these mountains it seldom attains one- 

 tenth part of the size of English trees. Every country carpen- 

 ter in Scotland knows the extreme difference between the dura- 

 tion of Highland and English oak for spokes to wheels. Many 

 hedge carpenters in both countries know the relative duration 

 of transplanted or plantation oaks (that is, young oaks thinned 

 from thriving plantations) and those from natural forests, when 

 employed as posts for railing. From different observations 

 which I have made in Monmouthshire and Herefordshire, the 



