LETTER II. 



15 



the South iVmerican forests are mentioned by Martius 

 with a girth of eighty-four feet at the base of the 

 trunk." * 



6. What do we learn from these statements ? The 

 height and thickness which individual trees of dif- 

 ferent sorts have been known to attain. But nothing 

 approaching the expression of a law. And doubtless, 

 of the trees specified, the measurements of many of 

 them were taken at a time when they were still grow- 

 ing in height, and still increasing in thickness ; or if 

 dead, reduced to this condition by the axe of the 

 forester, and felled while yet fresh and vigorous. 



7. M.Richard, in hhWoiiveaux EUmens de Botanique, 

 goes more expressly into the subject than Dr Balfour. 

 He has sections designated respectively " De la Duree 

 des Arbres/' " De la Hauteur des Arbres" and De 

 la Grosseur des ArbresJ'f Let us see whether now 

 we shall get the information we are in quest of. In 

 the first section, M. Richard merely tells us that trees 

 growing in a suitable soil may live for ages — the Olive 

 for about 300 years, the Oak for about 600, the 

 Boabab, according to the reckoning of M. Adanson, 

 for about 6000 years ; and further, that the Cedars of 

 Lebanon appear to be in a manner indestructible. 

 '^Les cedres du Liban paraissent en quelque sorte 

 indestructibles." Mark this singular expression. In 



* Class-Book of Botany, p. 438. 

 t 5ieme Edition, pp. 130, 131, 132. 



