44 Sketch of the latest Improvements (Jan. 



5. Schorl — Professor Bernhardi being of opinion that common 

 schorl, and several other species of minerals, might be constituted 

 into a genus, to which he proposed to give the name of touimaline, 

 requested Professor Bucholz to make an analysis of common schorl 

 to serve as a saqiple of this new genus. Bucholz accordingly made 

 three very careful analyses, two of schorl from St. Gotthard, and 

 one of sciiorl from Tyrol. The result was as follows: — 



Silica 35 000 



Alumina 31-500 



Magnesia 5*938 



Lime 0-062 



Oxide of iron 6*125 



Silica containing iron 0-125 



Manganese, a trace. 



Water 5-000 



Potash 1-333 



Loss 14-917 



100-000 



This loss he was not able to account for. He could neither find 

 any more alkali, nor any volatile matter whatever. The most pro- 

 bable substance seems to be fluoric acid. 1 do not perceive that 

 he sought for it particularly. 



6. Arragonite. — The discovery that arragonite contains about 

 four per cent, of carbonate of strontian, recently made by Professor 

 Stromeyer, is of considerable importance, by removing an anomaly 

 which hitherto had existed in mineralogy ; namely, the same che- 

 mical composition with a difference of external characters. It 

 shows us also how much analysts ought to be on their guard, and 

 how easy it is for the most skilful experimenters to overlook ingre- 

 dients that have a marked elfect upon the external characters of 

 minerals. 



6. Schorlous Beryl. — This mineral was analysed by Bucholz in 

 1804, who detected in it 1/ per cent, of fluoric acid. Since that 

 time Vauquelin (Ann.de Chim. Ixvii. 24/,) and Klaproth (Beitrage, 

 V. 57,) analysed this mineral. The former found five per cent, of 

 fluoric acid ; the second, four per cent. This great discordance 

 induced Bucholz to repeat his experiments, and his new analysis 

 agrees very nearly with his former one. He found the constituents 

 as follows : — 



Silica 35 



Aluuiina 48 



Oxide of iron 00*5 



Water 1 



Fluoric acid 16-5 



lOI-O 



