212 



«The steenstrupite is analyzed almost exactly according 

 to the methods of Lorenzen and Blomstrand.» 



«The mineral was decomposed with nitric acid (better 

 than hydrochloric acid) ; the indissolvable residue (very im- 

 pure silica) was weighed and the silica removed and found 

 as difference. The remainder was treated with sulphuric 

 acid, and after separation of niobic acid added to the filtrate 

 from the silica. The mixed filtrate , evaporated and partly 

 neutralised with ammonia, was precipitated with oxalic acid 

 (Ce, Y, Th). To the filtrate ammonia was added; the pre- 

 cipitate was ignited, dissolved in nitric acid and phosphoric 

 acid separated Avith ammonium molybdate; in the filtrate 

 the substances were separated as usual.» 



«Water was found directly by ignition with sodium 

 carbonate and absorption in calcium chloride tubes. Phos- 

 phoric acid Avas estimated in a special portion after the 

 silica had been removed.» 



«No higher oxides of Ce, Mn were found.» 

 By studying the above table it will be seen, that in 

 general there is an even process of development from I to 111, 

 which accordingly shows how the alteration of the steenstrupite 

 takes place The most remarkable phenomena found are : the 

 constant increase in the quantity of water, while the quantity 

 of soda, silica and phosphoric acid decreases considerably, and 

 the perfect oxydation of MnO to Mn^O^ and of Ce^O^ to CeO,^. 

 The complete disappearance of the fluorine in the more altered 

 formations is possibly also due to the process of alteration, 

 while the varying quantities of several of the other substances 

 must be supposed to be caused by casual reasons. 



On account of the great number of substances it is rather 

 difficult to establish a fixed formula for the steenstrupite. A 

 number of different combinations are possible, however it seems 

 that no one of them is much to be preferred to the others, 

 it is not even certain, that type 111 of the mineral represents 



