M. Scheerer's Observations on Elccolith and Nepheline, 1 1 1 



12. 



Silica 44-04 



Alumina 34*06 



Peroxide of iron . . 0*44 



Lime 2-01 



Potash 4-52 



Soda 15-91 



Magnesia .... trace 



Water 0*21 



101-19 



The silica, on dissolving it in carbonate of soda, was found 

 to be so pure that it only left 0'004« gr. insoluble matter. The 

 amount of water was adopted from the first determination. 

 The agreement of this analysis with the two former, sets it be- 

 yond all doubt that the foreign minerals which were present 

 in both the former had not exercised any influence on the 

 results. The quantity of alumina in analysis 12 seems, how- 

 ever, from some circumstance or other, to be stated too high, 

 as it is about 1 per cent, greater than in the analyses 10 and 

 11, and the analysis gives 1 per cent, overplus. However 

 this may be, it results from the three inquiries, 1st, that the 

 nepheline contains a larger quantity of lime than elasolith ; 

 2ndly, that soda and potash are contained in both. In these 

 two points my analyses differ entirely from those of Arfvedson. 

 He mentions, it is true, having found some lime, but that the 

 quantity was too small for accurate determination. It may 

 therefore be the case that all nephelines do not contain this 

 quantity of lime, amounting to 2 per cent., if the reason of Arf- 

 vedson' s not finding so considerable a quantity of lime is not to 

 be sought for in the method he employed; viz. instead of add- 

 ing oxalate of ammonia immediately to the liquid filtered from 

 the alumina, first neutralizing it with hydrochloric acid. The 

 point of neutralization might here be easily exceeded, and some 

 oxalate of lime remain dissolved in the fluid. That Arfvedson 

 found no potash, probably arises from his using for its detec- 

 tion a far more imperfect reagent than chloride of platinum, 

 viz. tartaric acid. 



6. White El&olith from Katzenbuchel in the Odenwalde. — 

 This variety is found in isolated crystals in dolerite (nepheline 

 rock), which breaks through the sandstone of the Katzen- 

 buchel. Prof. L. Gmelin has given an analysis of it in a 

 paper by him and Prof. Leonhardt, which I will here cite. 

 It gave 



