Intelligence and Miscellaneous Articles, 443 



ANALYSIS OF POONAHLITE. 



M. C. G. Gmelin remarks that this mineral belongs to the family 

 of zeolites, and its appearance is similar to that of the mesotype 

 species (skolerite, natrolite, for example). But whereas at present 

 the minerals ranged in the mesotype species have the angle of the 

 two faces of the prism 91° or 91° 38', that of the poonahlite, accord- 

 ing to the measurement of Brooke, is 92°, which induced him to con- 

 sider this mineral as a peculiar zeolite, and to name it poonahlite 

 from Poonah, the place at which it is found in the East Indies. The 

 poonahlite occurs in very long prisms, and among several hundreds, 

 none of the terminations were modified by planes ; it occurs in druses 

 in apophylite, and the rock which contains it. Its specific gravity is 

 2-2622. 



The analysis gave as its constituents, — 



Silica 4.5-120 



Alumina 30-446 



Lime 10-197 



Soda and traces of potash • . . 0-657 



Water 13-386 99-806. 



This agrees with the formula 



SCaSi-f-SAlSi + l^H. 



Poonahlite is therefore a variety of mesotype, the formula of which 

 has great analogy with skolerite and natrolite. 



PoonahUte .... 3 Ca Si + 5 AlSi + 12 H 



Skolerite 3 Ca Si -|- 3 Al Si -)- 8 H 



. NatBolite 3 Na Si + 3 Al Si -h 61^ 



Annates des Mines, torn. xvii. 



ANALYSIS OF WASSER-GLIMMER. BY M. MORIN. 



This mineral was found at the foot of a glacier of Mont Rose, in 

 Zermanthal, two years ago ; it has since been found at the Simplon 

 and several other places in the Valais. 



It has all the appearance of a mica, is lamellar, of a deep green 

 colour, opake, except at the angles, feels greasy and is scratched by 

 the nail ; the faces in the direction of the laminae are brilliant and 

 green, the lateral faces are duller and black ; by transmitted light 

 parallel to the laminas, a very marked ruby colour is observed. 



The crystals are easily divided into very thin laminae by the knife ; 

 they are flexible, but quite inelastic ; the cleavage in any other direc- 

 tion is difficult, still it is ascertainable that the fundamental form is 

 a right prism whose base is a parallelogram ; two of the edges of 

 the prism are usually replaced by a plane. 



At 212° the wasser- glimmer loses no weight, but by calcination 

 it loses much water ; its powder is white, |but by long calcining it 

 becomes yellow. Hydrochloric acid partly attacks it with the evo- 

 lution of chlorine, but sulphuric acid does not act upon it ; it 

 contains no alkali. The analyses made either with carbonate of 

 potash or carbonate of barytcs, gave tlic following results : — 



