282 



Klaproth on the Chemical Analysis. 



sulphur, which being deducted from the joint amount of the sul- 

 phur and charcoal, amounting to 225 grains (E6) leave 196.5 

 grains for the weight of the charcoal. 



H. 



Assuming that 1000 parts of crystallized alum yield upon 

 average, when decomposed by muriate of baryta, 945 grains of 

 sulphate of baryta, it follows that 1000 parts of the alum ore 

 of Freienwald, containing 28.5 of sulphur, should produce sul- 

 phuric acid sufficient (with the due addition of potassa) to form 

 260 parts of alum, for which scarcely one-sixth part of the 

 alumine in the ore is required. But the quantity of alum pro- 

 duced at the works, falls infinitely short of this estimate in con- 

 sequence of the very imperfect acidification of the sulphur. 



I. 



The following view of the components of this alum ore is sug- 

 gested by the above experiments. 



Sulphur G . . 



Carbon G . . 



Alumina De . . 



Silica Drf 



Black oxide of iron (with a veryT 



slight trace of manganese D/J 

 Of which deduct for the compo-'j 



sition of sulphate of iron J 



72.5 



8.5 



28.50 

 196.50 

 160. 

 400. 



64. 



1012. 



Some of the above results, however, require further investiga- 

 tion, and the magnesia is probably in the state of sulphate in the 

 ore. The excess of 1.5 per cent, in the analysis is insignificant 

 in such experiments. 



