64 TEXTURE OF VEGETABLES. 



ers which compose its trunk. It has even been assert 

 ed that we may know what winters have been pecul- 

 iarly severe, by the hardness of the annual plates, and 

 what summers have been mild and serene by their su- 

 perior thickness. Duhamel having discovered some 

 exceptions to the truth of this general proposition was 

 led to reject it entirely, but his observations are not 

 deemed sufficient to invalidate an opinion which most 

 botanists have adopted. " It is very true that there 

 may be occasional interruptions in the formation of the 

 wood from cold or fickle seasons, and in some trees the 

 thin intermediate layers, hardly discernible in general, 

 which unite to form the principal or annual ones, may, 

 from such fluctuation of seasons, become more distinct 

 than is natural to them. Such intermediate layers are 

 even found more numerous in some trees of the same 

 species and age than in others. But as there is always 

 a most material difference between summer and winter, 

 so I believe there will always be a clear distinction 

 between the annual rings of such trees as shew them 

 at all. Trees of hot countries indeed, as Mahogany, 

 und evergreens in general, have them but indistinctly 

 marked ; yet even in these they are to be seen."* 



The divergent plates sometimes termed silver grain 

 in allusion to their singular brightness, are particularly 

 numerous in the Maple and large in the Oak. They 

 seem to bind together the annual circles, and to increase 

 the strength of timber which without these connecting 

 bands, would have been easily shattered to pieces : 

 nor is it uncommon to see the former separated from 

 each other, in consequence of the destruction of their 

 silver grain. Each of these concentric layers is divisi- 



* Smith. 



