3o6 DESCRIPTION OF THE MUSEUM. 



powder for killing flies. In the state of sulphuret 

 it presents two varieties of colour, very useful 

 for painting : one is the realgar, of an orange- 

 red colour; and the other orpiment, of a beau- 

 tiful citron-yellow. 



Manganese is of great use in the manufacturing 

 of flint-glass and mirrors. Antimony, which im- 

 mediately follows, is used in medicine, especially 

 as an emetic. It serves also in the casting of 

 printers 7 types, and for the composition of me- 

 tallic mirrors. In the fifty-eighth case we see 

 some fine specimens of sulphuret of antimony in 

 needles of a reddish brown colour, and in very 

 silky fdaments. 



Uranium, molybdena, titanium, tungsten, tel- 

 lurium and chrome, the modifications of which 

 furnish the remainder of this and the next case, 

 are metals but little known, and almost without 

 use, if we except the last of them, which was 

 discovered by M. Yauquelin, and is successfully 

 employed in painting porcelain and staining 

 glass. 



Here terminates the collection of minerals, pro- 

 perly so called ; one of the most precious in exis- 

 tence, on account of the great number of choice 

 specimens which it possesses, and the order 

 in which it is distributed. It will be proper 

 to remind our readers, that the specimens of this 



