1824.] Mr. Levy on a new Mineral Substance. 275 



2. The oxidum manganoso-manganicum of Arfwedson is a 

 compound of 1 atom protoxide and 2 atoms deutoxide. 



1 atom protoxide 4-5 



2 atoms deutoxide 10*0 



3VL4-5 



4-833 



so that its atomic weight (reduced to the lowest terms) is 4-833. 



3. According to Berzelius the atomic weight of manganese is 

 7-1157, and the names and constituents of the different oxides 

 are, according to him, as follows : 



Composition. 

 Atomic weight. Metal. Oxygen. 



2. Oxydule .... 91157 .... 7-1157 + 2 



3. Oxide 10-1157 ....7-1157 + 3 



4. Superoxide.. 10-1157 .... 7-1157 + 4 



4. Berzelius represents these three oxides by the following 

 symbols : 



1. Protoxide Mn. 



2. Deutoxide Mn. 



3. Tritoxide Mn. 



denoting the number of atoms of oxygen by the dots above the 

 letters Mn. 



Article VI. 



Account of a new Mineral Substance. By M. Levy, MA. 

 in the University of Paris. 



(To the Editor of the Annals of Philosophy.) 



DEAR SIR, Marc/t 12, 1824. 



Upon a specimen from Arendal, belonging to Mr. Turner's 

 collection, 1 have lately observed with cleavelandite,* flesh- 

 coloured felspar, and green amphibole, some small brilliant black 

 crystals, the description of which I now send you, because I 

 believe they belong to a new mineral species. Their form is 



• The substance I call here cleavelandite forms the greatest part of the specimen ; it 

 has much the appearance of cleavelandite, but however 1 have not been able under the 

 small particles I have detached to obtain cleavage sufficiently brilliant tor measurement. 



t2 



