462 tmperial Institute of Fraticei 



Some experiments and observations were slated, which 

 were supposed to render it probable tiial the hilier principle 

 is a compound basis, which by uniting to oxygen, or bv un- 

 dergoing more complicated processes, might change its 

 nature so tar as to become an acid. 



IMPERIAL INSTITUTE OF FRANCE. 

 [Continued from p. 394.] 



Mineralogy and Geology. 



The late professor Abilgaard, of Copenhagen, discovered 

 some years ago a combination of alumine and fluoric acid, 

 hitherto unknown to mineralogists. M. Brunn Neorgardt, 

 of the King of Denmark's household, published a histo- 

 rical notice of this very rare substance, which came from 

 Greenland : he describes pieces in which it is surrounded 

 by other minerals, a circumstance which may lead to the 

 discovery of the kind of soil in which it is found. 



M. Lelievre, niember of the class, has published another 

 notice of a gray mineral which he discovered in some pieces 

 of granitic rock sent to him from Piedmont by M. 

 Muthuon, mining engineer. 



M. Brongniart has completed the mineralogical descrip- 

 tion of the environs of Paris, which he undertook in 

 concert with M. Cuvier, by taking the level of the principal 

 eminences in the district which he describes. The results 

 of their joint labours have been given to the world, and 

 will form a valuable addition to M. Cuvier's researches on 

 fossil bones, 



M. DauxierLavavsse, formerly a colonist of Saint Lucia, 

 has presented to the class a geological description of Tri- 

 nidad, and other islands adjoining the mouth of the 

 Oronooko. The latter are very low, and are frequently 

 inundated by the river, of which they seem to be mere alluvia. 

 In Trinidad there is a lake which produces abundance of 

 bitumen, and towards the southern shore the sea also 

 throws up the same substance at two places. Two adjacent 

 hillocks have small craters, and give out sulphureous va- 

 pours. We there find sulphur, alum, and crystallized 

 vitriol. In another pari of the island there is a mine of 

 plumbago and coal. To conclude, Trinidad resembles in 

 such a sti iking manner the adjoining continent in the nature 

 of its rocks, that there is every reason to believe, according 

 lo M. Lavavsse, that it was anciently part of the same con- 

 tinent. Gray schistus or argill is every where prevalent : 

 calcareous stone and gypsum, so abundant in the Antilles, 

 are here very rare. 



Vegetalle 



