M. Scheerer's Observations on Elccolith and, Nepheline, 109 



iferous syenite of Fredriksv'arn. It must be considered, as 

 it were, as a granite in which the quartz is replaced by elseo- 

 lith. On account of its evident peculiarity and its large dis- 

 tribution, Professor G. Rose has proposed for it the name mi- 

 ascite (from the river Mias in the neighbourhood of its occur- 

 rence). Its specific gravity I found to be 2*60. 



Two analyses of this mineral have recently been published 

 by M. Bromeis*, who obtained the following results : — 



Silica 42*51 42*33 



Alumina. . . . 33*73 34*39 



Peroxide of iron . trace trace 



Lime 0*20 0*47 



Soda 14*01 16*26 



Potash .... 6*91 5*95 



Magnesia . . . 0*77 0*45 



Water .... 0*92 0*92 



99*05 100*77 

 Mr. Francis and I have likewise examined this mineral. 

 The result 8 is that which Mr. Francis obtained ; the result 9 

 that which I obtained by analysis : — 



8. 9. 



Silica 44*30 44*07 



Alumina. . . . 33*25 33*12 



Peroxide of iron . 0*82 0*57 



Lime 0*32 0*26 



Soda 16*02 15*70 



Potash .... 5*S2 5*69 



Magnesia . . . 0*07 trace 



Water .... 0*00 0*90 



100*60 100*31 



The results of the two last-mentioned analyses differ from 

 those of M. Bromeis, particularly in the amount of silica. I 

 shall subsequently return to this point. 



5. Nepheline from Monte Somma (Vesuvius). — This mineral 

 occurs very differently from the preceding ones, it always 

 being found crystallized in 6-sided prisms with terminal faces 

 perpendicular to the axis, combined with one or two hexa- 

 gonal pyramids. It is situated in cavities of the dolomite, 

 accompanied by garnet, vesuvian, anorthite, glassy felspar, 

 ike. All these minerals present exactly the appearance of 



* Pogg. Annalen, vol. xlviii. p. 577. 



