432 THE UNIA'^EESE. 



CHAPTEE V. 



GROWTH. 



The growth of our trees was for long an impenetrable 

 mystery. 



Duhamel mamtained that it was the bark which pro- 

 duced the wood, and for more than a centmy this was 

 believed on the faith of the celebrated academician who 

 had made so many experiments on the subject. It did 

 not occur to any one to ask him from whence the bark 

 came. 



After many discussions it has at last been shown that 

 the woody structure and its envelope grow at their junc- 

 tion, each in its own Avay: the bark growing towards the 

 interior, the wood outwards by concentric layers which 

 are piled up one above the other. One is produced each 

 year, so that by counting the circular zones at the base of 

 a trunk, their number gives the exact age of a tree. 



Long before this fact had been taught as a dogma by 

 botanists, it was known to the vidgar. Mention is made 

 of it in Michel Montaigne's Voyage en Italle, a singular 

 production, wherein, instead of Italy, Ave find only a list 

 and the effects of different remedies Avhich the illustrious 

 Mayor of Bordeaux employed in every toAvn he passed 

 through. A journeyman turner showed him that he could 

 compute the age of trees very Avell from sections of them. 

 "He taught me," he says, "that all trees bear as many 



