THE LONGEVITY OF TREES. 



3 2 3 



of its growth ; and the rate thus ascertained may be applied to other 

 trees of its kind whose diameter is known, although its woody layers 

 he inaccessible. In this way the age of many trees has been esti- 

 mated. The relation between the age of a tree and its annual rings 

 was first noticed and applied by Montaigne, in 1581. 



Fi<;. ?.. 



Pauu-Trees. 



But this method of ascertaining a tree's age does not apply to the 

 class Endogens, in which the growth is internal, as shown in Fig. 2. 



