1824.] M. Arfwedson's Analysis of some Minerals, 345 



Thus the constituents of the mineral have been found to be : 

 Silica (a).. 0-625 



(6) . . 0007 



(d).. 0-007 



. . Per cent. 



0-639 or 41-87 containing oxygen = 21-06 



Alumina 0-314 20-57 = 9-60 



Lime 0-518 33-94 = 9-53 



Oxide of iron .... 0-060 3-93 = 1-20 



Manganese with 



■&* 



magnesia 0-006 0-39 



1-537 100-70 

 We perceive from this table that the oxygen of the silica is 

 equal to that in the bases. Further, that the alumina and lime 

 have the same quantity of oxygen, and each eight times as much 

 as the oxide of iron. Thus the formula exhibiting the constitu- 

 tion of the mineral isFS + 8AS + 8CS. 



Klaoroth's analysis of cinnamon stone from Ceylon gave* 



F Silica. 38-80 



Alumina 21*20 



Lime 31-25 



Oxide of iron 6-50 



Loss 2-2o 



10000 

 That result does not deviate far from mine ; but as far as 

 regards the smallest ingredient, oxide of iron, the considerable 

 excess of it occasions quite a different formula. It becomes F S 

 + 4CS + 5AS. It is possible that Klaproth underrates both 

 the lime and the alumina, because he separated the former by 

 carbonate of soda, and the latter from its solution in potash by 

 means of sal ammoniac. His formula, therefore, may be a good 

 deal faulty. The formula which I found is considerably simpler, 

 and, therefore, more likely to be correct. 



I conceive that we have thus found reason to consider the 

 mineral from Malsio just analyzed as a real cinnamon stone, at 

 least as long as Klaproth's analysis continues unrepeated and 



unconfirmed. 



Brasilian Chrysoberyl. 



Our knowledge of the constituents of this mineral is derived 

 from Klaproth's°analysis,t according to which it is composed of 



Alumina 71-50 



Lime 6-00 



Oxide of iron 1 '50 



Silica 18-00 



97-00 

 • Beitrage, v. 142. ♦ W* '• 102 - 



