14 Biographical Memoir cf M. DaubentoH, 



tion to the fact, that all trees do not grow by external and con- 

 centric layers. A pahn trunk, which he examined, shewed none 

 of these layers. Excited by this observation, he perceived that' 

 the growth of that tree takes place by the prolongation of fibres 

 from the centre, which are developed into leaves. He explained 

 by this circumstance, why the trunk of the palm does not inii 

 crease in thickness as it grows old, and why it retains the SafaW 

 size in its whole length* ; but he did not piish his-inquifies fi^l^; 

 ther. M. Desfontaines, who had observed the same circiim-i 

 stance long before, exhausted, so to speak, the subject, by sh^^- 

 ing that these two modes of growth distinguish the trees whcise 

 seeds have two cotyledons, from those which have but one^ arid 

 by establishing on this important discovery, a division which 

 will for ever be fundamental in botany -|-. v sn i.'^:>;f .'t 



Daubenton was also the first who discovered tracheee'in the 

 bark, that is to say, those shining elastic vessels, often filled with 

 air, which others had discovered in the wood. :i!Joisj^.Mij 



Mineralogy has made so much; progress of late year^,'"ichat' 

 Daubenton's labours in this department of natural history are 

 now almost eclipsed, and, perhaps, there will only remain'";^ 

 him the glory of having trained to the science the individual ii^hof 

 has carried it farthest: it was he who was M. Haliy's Waste^n 

 He published some ingenious ideas, however, on the formatioit^ 

 of alabasters and stalactites l^ on the causes of arborescences in' 

 stones II, on figured marbles, and descriptions of minerals little 

 known at the time §. It is true that his distribution of predou^- 

 stones is not accordant with their true nature; but it giVe^^ at 

 least some jn-ecision to the nomenclature of their <;oldur^^."'«'^^'^ 



In all those writing^s there is evinced'the peculiar kind of tieletit* 

 which he possessed,— a patience^ which would never allow him- 

 to form conj^ectu res respecting Nature, because it taught him not"' 

 tOi despair of forcing her to explain herself, by repeating his itt-' 



• Leyohs de I'Ecole Nonnale. 



t Memoiresde Tlnetitut Natippal, Clasee de Physique, t. i. 



X Memoires de VAcademie for 1754, p. 237. H Ibid, for 1782, p. 067. 



§ Ibid, for 1781. 



% See also his Tableau Methodique des MineraiiXf of whicfi' the fei-st edition 

 M-as published in 1784, the fifth in 1796. 



