181 Scientijic InkUi(icncc — Miitira'vjii "'"^ Clivinisltif. 



tlie production of the colour. The colouring matter in artificial ultra- 

 marines is partly of a fine blue, and partly of a fine green tint. The 

 latter, by contiuued heating in an open vessel, passes into the for- 

 mer ; whieh, Eisner says, takes place, because the blue colour re- 

 quires the combination of a larger quantity of sulphur with the so- 

 dium. This is effected when a portion of the sulphur is converted 

 into sulphuric acid, which removes soda from the sulphuret, by 

 which means the latter becomes comparatively richer in sulphur. 

 On this account the natural as well as the artificial ultramarine al- 

 ways contains sulphuric acid. {Bcrzelkis" Jahrrs-BcricJit, 1842.) 



20. Pcnnine.—Yiohel has described, in Poggendorfl^'s Annals, a 

 mineral from the Matter or Nikolai valley, in the Pennine chain of 

 the Alps, which has been analysed by Schweitzer, and has received 

 the name of Pennine. It sometimes occurs in hexagonal tables, some- 

 times in streaked prisms ; its colour is blackish green to leek green ; 

 it is translucent in thin plates; but, at right angles to the principal 

 axis, it is brown or hyacinth red. Hardness between that ol" gypsum 

 and calcareous spar. Its composition is — 



OMgcn. 



33.07 ■ 17.07 



0.60 4. .•3.5 



''■''' -■'■'] ,5.31 



3-2M4 12.70 J 



12 58 10.22 



98.08 00.04 

 It docs not seem possible to deduce a proper formula from the re- 

 sult of the analysis. It is plain, however, that its composition ap- 

 proaches that of the chloritic minerals. fBcrzdlan'' Jalircs-Bcr'icht, 

 2\st Jahrgang, p. 177. 



21. Plathia in the Au/iferotis Sand of the Bhine. — M. J, Diibc- 

 reiner has detected a small quantity of platina in the auriferous sand 

 of the Rhine. The amount was only 0.4 of a grain in 2 ounces. 



22. Villnrskc — M. Dufrenoy (Comptes Bendai', vol. xiv. p. 697) 

 has given the designation to a new mineral, in honour of M. Villars, 

 the author of a Natural History of Dauphiny. It was recently found 

 by M. Bertrand de Lom in a vein of iron-ore at Traversella, in Pied- 

 mont, and is there associated with dolomite, mica, quartz, and do- 

 decahedral crystals of magnetic iron-ore. The Villarsite has a yel- 

 lowish-green colour, and a granular fracture ; and in these respects 

 bears a considerable resemblance to some of the Arendal apatites. 

 The primitive form is a right rhombic prism of 119° 59', and the 

 crystals examined were rhombic octahedrons with truncated summits. 

 The following is its composition — 



