Intelligence and Miscellaneous Articles. 77 



ties from Schwarzenstein in Zillerthal, from Achmatof in Siberia, from 

 Grenier in Zillerthal, and from Roures near Salzbourg. They were 

 treated with sulphuric acid in a platina crucible ; the excess of acid 

 was expelled and the residue treated with hydrochloric acid; the 

 iron and alumina were precipitated with carbonate of barytes, and 

 the alkalies were sought for but not found. 

 The results were — 



Schwarzenstein. Achmatof. 



Silica 32-68 31-14 



Alumina 14-57 17*14 



Magnesia 33-11 3440 



Protoxide of iron 597 03-85 



■ ■ manganese 0-28 0'53 



Water 12-10 12*20 



Gangue 1'02 Q-85 



99-73 100-11 



Zillerthal. Roures. 



Silica 27-32 26-96 



Alumina 20*89 18-47 



Magnesia 24*69 14-69 



Protoxide of iron 15'23 26-87 



manganese 0*47 0-62 



Water 12-00 1045 



100-60 Gangue. 1*24 



99-30 

 The composition of the first two chlorites differs essentially from 

 that of the two latter; and M. Kobell considers that the first two 

 form a new species, to which he gives the name of repidolite (pierre 

 en eventail). 



The repidolite of Schwarzenstein is of an emerald-green colour by 

 transmitted light, and crystallizes in hexagonal tables with trian- 

 gular aggregated laminae ; it is accompanied with amianthus. 



The repidolite of Achmatof is of an emerald-green colour parallel 

 to one of its axes, and of an asparagus-green perpendicular to it ; 

 its crystallization is hexagonal, and it is associated with garnet. 



The chlorite of Zillerthal is penetrated with crystals of magnetic 

 iron, and becomes black before the blow-pipe ; that of Roures also 

 becomes black when heated by the blow-pipe, and is more fusible 

 than that of Zillerthal. — Annales des Mines, tome xvii. 



ANALYSIS OF THE TACHYLYTE OF VOGELSGEBIRGE. 

 BY M. KLETT. 



Ten years ago the late Professor Humdeshagen gave the analysis 

 of a mineral under the name of tachylyte of Vogelsgebirge, which 

 was perfectly similar to that of Sasebuhl ; of this there is no ana- 

 lysis, and we have that only of the mineral from Vogelsgebirge ; this 

 mineral has a specific gravity of 2*7144; before the blow-pipe it 

 fuses into an opake glass free from bubbles ; fragments of consi- 

 derable size fuse into a globule on charcoal ; with microscomic salt 



