442 Intelligence and Miscellaneous Articles. 



The fonnula deduced from the above analyses is 



^jSi°- + 4ASi2+ 6Aq. 



Gismondine cannot therefore be confounded with harmotome, al- 

 though it considerably approaches it. As to the crystalUzation, it is 

 very possible that it belongs to the prism with a square base ; al- 

 though it resembles harmotome in its crystallization, it wants the 

 re-entering angles, which are so common in the harmotome, and 

 which are characteristic of its form. — Annales des Mines, torn, xvii. 



ANALYSIS OF THULITE. BY M. C. G. GMELIN. 

 Pure thulite occurs in crystalline masses of a rose and blood-red 

 colour, with quartz, fluor spar, and idocrase, coloured with oxide of 

 copper, at Suland near Tellemark in Norway. Thomson found it to 

 consist of — 



Silica 46-10 



Oxide of cerium 25*95 



Lime 1250 



Oxide of iron 5*48 



Potash 8-00 



Water , 1-58 99'55. 



M. Gmelin states that this extraordinary result induced him to 

 analj'^se a very pure specimen of thulite, which he obtained several 

 years since from Prof. Esmark of Christiana. He obtained — 



Silica 42-808 



Alumina 31-144 



Lime 18-726 



Soda and trace of potash .. 1-891 



Oxide of u-on 2-888 



Oxide of manganese 1-635 



Water 0-640 99*132. 



This agrees perfectly with the previous analysis of Berzelius 

 (Coynptes Rendus, N. 12. S. 217), who does not find any oxide of 

 cerium in thuhte ; Thomson must therefore have analysed a different 

 mineral. According to the preceding analyses, Brooke and Levy 

 (Phil. Mag. 1831, vol. x, p. 109) announced that thulite approxi- 

 mated to epidote, which is perfectly confirmed, for we have 



ThuUte (Ca, Fe, Mn)3 Si + 2 Al Si 



Epidote (Ca, Fe)', Si^ + 2 Al Si 



Zoisite Ca, Si + 2 Al Si. 



Thulite, therefore, is only a variety of epidote. — Annales des Mines, 

 tom. xvii. 



[We may remark that the crystalline form of zoisite is the same 

 as that of euclase, and has not a single face or cleavage in common 

 with epidote.] — Ed. Puil. Mag., &c. 



