Intelligence and Miscella?ieous Articles. 153 



2 atoms muriatic acid 9'25 



1 atom peroxide of gold .... 28' 

 5 atoms water 5"625 



42-875 

 Dr. Thomson then proceeds to show, in opposition to the views 

 of Berzelius, that the permuriate of tin, like the muriate of gold, is 

 more probably a muriate than a chloride. — Ibid. p. 182. 



OXAHEVRITE — A NEW MINERAL. 

 This substance was brought from the hot-spring of Oxhaver in 

 the north-east of Iceland ; it occurs in petrifactions, in which the 

 wood has been replaced by calcareous spar of a fine ochre-yellow 

 colour, and more or less crystallized ; it occurs in thin veins, in 

 amorphous masses, in aggregated groups of crystals, and sometimes 

 in insulated crystals implanted in the calcareous spar. 



Dr. Brewster states that the crystals are acute octahedrons, with 

 a square base ; the angles at the base are truncated by planes pa- 

 rallel to the axis of the octahedron, and equally inclined to the 

 adjacent sides of the base, so as to form, when enlarged, the faces 

 of a square prism. Dr. Brewster observes a very remarkable pro- 

 perty in the crystals of this substance, and which he has never be- 

 fore seen. Every face of the octahedron is a surface of double 

 curvature, in consequence of which the maximum angle of the two 

 opposite faces of the pyramid is 58°, while the minimum angle is 

 4:2^, giving a change of inclination of no less than 16°. The maxi- 

 mum inclination occurs at the base, and at the vertex of the pyra- 

 mid, and the minimum inclination at an intermediate point. The 

 colour of the crystals is light-gray, leek-green, olive-green, and 

 reddish-brown; they are nearly as hard as apatite, sp. gr. 2*218. 

 Their general size is about one-tenth of an inch in length ; their 

 surfaces are even, but not brilliant, and the small truncations of the 

 angles at the base of the pyramid are more imperfect than those of 

 the octahedron, the imperfections having the direction of the axis. 

 They cleave with some facility perpendicular to the axis, but in no 

 other direction ; the plane of cleavage is considerably rounded, 

 the convex surface being turned towards the apex of the pyramid. 

 Dr. Turner has analysed this mineral with the following results : 



Silica 50-76 



Lime 22-39 



Potash 4-18 



Peroxide of iron 3-39 



Alumina 1-00 



Fluoric acid a trace. 



Water 17-3(J 



9908 



Dr. Turner observes, that as the proportions of silica, lime, potash, 



and water, are so nearly the same as those obtained by Berzelius 



from the apophyllite and tesselite, it admits of doubt whether the 



New Scries. Vol 2. No. H. Auanst 1827. X iron 



