Analysis of some Steatites, 139 



Analysis of the yellowish compact Talc (Speckste'm). 



1. A hundred parts of this stone strongly calcined lost 

 5 parts. 



2. Heated afterwards with twice its weight of. potash in a 

 silver crucible no fusion took place, but the matter was? 

 greatly increased in bulk, and had become homogeneous. 



3. This was diffused in water, and dissolved in muriatic 

 ^cid. The solution, being evaporated, became gelatinous, 

 towards the end of the operation. 



4. The matter being dried and washed, a white powder 

 remained, which, after calcination, weighed 56 parts. 



5. The silex having been separated by lixiviation, the 

 liquor was mixed with a small quantity of muriatic acid, 

 and ammonia was afterward poured in, which formed in it 

 a copious white flocculent precipitate. 



6. The liquor being filtered, the precipitate was washed 

 and dried. This was alumine, and weighed 30 parts. The 

 alumine dissolved entirely in sulphuric acid, and its solu- 

 tion, saturated with the requisite quantity of potash, af- 

 forded very pure alum : but the mother water, evaporated 

 afresh, yielded 5i : parts of sulphate of lime crystallized in 

 needles. Thus with the assistance of the alumine the am- 

 monia precipitated the lime from its solution in muriatic acid. 



7.. The liquor from which the alumine had been sepa- 

 rated gave^io precipitate with carbonate of soda, even assisted 

 by long boiling. The speckstein therefore contains no mag- 

 nesia, like the two preceding varieties. — But in recapitulat- 

 ing the products of this analysis we find only 93 parts; 

 namely, 



Silex - ' , 56 



, Alumine 29 



Lime ...... 2 



Iron 1 



Water 5 



93 



A loss so considerable, which is not common in such 

 analyses carefully executed, led me to suspect that the 

 compact talc contained some other principle, which the 



processes 



