Mineralogy. 185 



3d, What are the substances which may serve as a ferment for the ace- 

 tous fermentation, and what are the essential characters of these kinds of 

 ferments ? 



4th, What influence does the air exert over the acetous fermentation ? 

 Is its presence essential ? In which case how does it act ? Is its office the 

 same as in the alcoholic fermentation, or, if absorbed, does it become a con- 

 stituent part of the acid, or give rise to foreign products ? 



5th, Finally, To establish a theory of the acetous fermentation in har- 

 mony with all the facts observed. 



The Society will give a medal worth 1000 francs to the author who shall 

 solve all the proposed questions completely. Or, if not entirely solved, the 

 Society will grant a medal worth 500 francs to the person who treats the 

 greatest number of questions in a satisfactory manner. 



The memoirs to be written in French or Latin, and to be delivered to 

 M. Henry, Secretary of the Society, before the 1st of April 1827. A 

 motto is to be attached to the paper, corresponding to that on a sealed 

 packet, containing the name of the author. Foreigners are invited to con- 

 tend for the prize. — Journal de Pharmacies Feb. 1826. 



III. NATUKAL HISTORY. 



MINERALOGY. 



19. Selenium found in Bavaria. — Mr Hermann von Meyer, of Frankfort, 

 has found this substance in the sulphuric acid made at Bodenmais in 

 Bavaria. He has not re-examined the one from which it is produced, 

 and, therefore, he has not discovered whether it occurs in some particular 

 combination, or is merely contained in the iron pyrites from which the 

 acid is obtained, by first converting it into dry sulphate of iron, and then 

 distilling the acid from it. 



20. Uran-bloom, a new mineral species. — Professor £ippe, of Prague, has 

 given the following account of this mineral, which was sent to him as 

 something new, by Mr Peschka, of Joachimsthal. It is of a very pure 

 and bright yellow colour, between the lemon-yellow and sulphur-yellow 

 tints. It occurs in crystalline flakes, too small to allow of being deter- 

 mined in respect to their regular form, and possessing but little lustre. 

 It is very soft and opaque. When slightly heated before the blowpipe, 

 the colour is changed into orange-yellow. The mineral is soluble with 

 effervescence in acids, producing a yellow solution, which affords a brown 

 precipitate by prussiate of potash. It appears, therefore, to be a carbo- 

 bonate of uranium. The uran-bloom has been found in a silver-vein, 

 called the Elias, at Joachimsthal, in Bohemia, disposed on uranium-ore, 

 along with the yellow oxide, and sometimes accompanied with pharmaco- 

 iite. It is distinguished from uran-ochre, chiefly by its stronger lustre 

 and paler colour, and from sulphate of uranium, described by Professor 

 John, by its insolubility in water. It appears to have been produced by 

 the decomposition of the uranium-ore, on which it forms a coating. 

 —■Verhandlungen der Gesellscliaft des Bbhmischen Museums, vol. ii. 1824. 



