106 On tun Longevity of Trees 



In 1777 llio walors^of tlio main stream of the Gariep or Orange 

 River had been discovered ; and in 1801 the Batthipee Tribe of 

 the Bcchuana had been visited at its city of Lettakoo, and 

 some vague information of the surrounding country obtained. 

 Within the Colonial limits just described, discovery had gone 

 on as the vvants or cupidity of the Settlers dictated, or the 

 weakness of the Government permitted, hut to trace which is 

 jiot at present requisite, 



Note. — The Writer of the present article is in hopes to be able to pro- 

 cure an cnj^raving of the sketch which he prepared for its illustration, for 

 the next number of the Journal. 



JExtracts from an Article entitled " On the Longevity of 

 Trees and the Means of ascertaining it. By Professor 

 De Candolie," 



[From the Edinburgh New Philosophical Journal, October 1833.] 



The longevity of certain trees is truly interesting-, were it 

 uierely from motives of curiosity. If we prize every document 

 of antiquity, why should we not attach a higher degree of im- 

 portance, to know whether such a tree be the cotemporary of 

 the oldest generations? In certain cases, this knowledge might 

 throw light on the history of monuments, as that of monuments 

 on the history of the trees in their vicinity. This discussion 

 may be useful in a history of the very globe wo inhabit. If the 

 known number of veterans in vegetation increases in time to 

 come, if we succeed in determining their ag;e with greater pre- 

 cision, may we not find in such facts some means of fixing the 

 approximate date of the last revolutions of the globe ? 



Every one knows, that the vegetables designed for the forma- 

 tion of trees may be ranged under two great series. The first, 

 which is the more numerous, has a trunk composed of a woody 

 body and bark : it grows by the annual addition of a new 

 ligneous layer on the outside of the preceding layers under the 

 hark. In consequence of these new layers being the youngest 

 nnd the most outward, they liave been called exoyenovs in 

 reference to their increase, and dicotyledonous when we allude 

 to their germination. The second series, on the contrary, is 

 composed of vegetables whose trunks, very cylindrical, and sel- 

 dom hrnnching, merely present a woody body, properly speak- 

 ing without bark, whose outer fibres are older and harder, and 

 the inner younger and softer. They have been called endoge- 

 vovs in consequence of this latter circumstance, which term is 

 employed when we allude to their growth, which is synonymous 

 with that of monocotijlcdomus, by which they arc distingnishod 



