— and on the Means of ascertaining it. S45 



of the trunk bare, and marked with circular rings, nearly at re- 

 gular distances, at least during the greater period of their life ; 

 the others, like the Dracaena, have the trunk branching, with- 

 out rings. The age of the palm-trees may be estimated in two 

 ways, very analogous to one another: — 1. By the height to 

 which they reach, compared with the empiric knowledge of the 

 time which each species requires in growing ; 2. By the nume- 

 rous rings and their mean distance, compared with the height of 

 the trunk. Both of these modes are principally based on a 

 knowledge of the height of the trees, just in the same way as 

 the study of the age of exogenous trees is founded on their 

 thickness. It is therefore of essential importance, to advise tra- 

 vellers to take a correct note of the extreme length of the trunk 

 of every kind of palm-tree. They should also be requested to 

 measure the height of every tree whose age is known, and to as- 

 certain, by an examination, if the rings seen on the outside real- 

 ly indicate, as it is said, the annual growth, or any other pe- 

 riod. 



The first method, on being applied to the date-tree, seems to 

 afford results in conformity with truth. There was a date- 

 tree in 1709 at Cavalaire, in Provence, 50 feet in height, 

 which had been planted in 1709. The greatest height of those 

 in Egypt and Barbary. is 60 feet, and the Arabians reckon that 

 their age rarely exceeds two or three centuries. It is unneces- 

 sary to ascertain in what proportions the rapidity of the growth 

 of the date-tree decreases at diflPerent periods. 



Assuming that the external rings of the trunk indicate the 

 years, we may estimate the approximate age of the Brazil palm- 

 trees, according to the principles laid down by M. de Marti us, 

 i^ his magnificent work, as follows : 



