1835.] Improvements in Science. 271 



It has been named in honour of Professor J. Dana. 

 (Americ. Journ. iv. 386. ) 



13. Hypochlorite. — This mineral forms a superficial coat- 

 ing on clayslate. It is associated with native bismuth, 

 arsenical cobalt, sulphur of arsenic, and quartz. Its texture 

 is foliated ; cleavage compact or slaty ; lustre slightly 

 vitreous ; colour green, more or less translucid. Sp. gr. 

 2-935-3-045. (Ann. des Mines, vi.) 



14. — Antimonial Nickel. (Poggendorff Ann. xxxi. 134.) 

 H. Stromeyer and Hausmann have examined this mineral. 

 It was found by Volkmar in the Andreasberger mountains, 

 mixed with calcareous spar, galena, cobalt ore, and resembles 

 Kupfer nickel, but is easily distinguished by the colour. It 

 occurs in crystals of six-sided tables; fracture uneven. 

 The extremities of the tables possess a strong metallic lustre. 

 The colour of fresh pieces is copper- red, with a strong tinge 

 of violet. The powder has a reddish-brown colour, and is 

 darker than the colour of the fracture. It is not magnetic. 

 Before the blowpipe it gives out neither a smell of garlic 

 nor sulphur. Heated in a glass tube some antimony 

 sublimes. Nitric acid separates the sulphur when galena 

 is contained in it. The solution of this mineral in nitric, 

 displaced by tartaric acid, gives, with sulphuretted hydro- 

 gen, an orange coloured precipitate, which is taken up by 

 potash, and, by reduction with hydrogen, is converted into 

 antimony. The solution, freed from antimony, affords, 

 with carbonate of soda, an apple-green precipitate, which 

 dissolves in ammonia with a sapphire blue colour. It con- 

 sists, according to analysis, of 



Nickel 28-946 - 27-054 



Antimony 63-734 - 59-706 



Iron 0-866 - 0-842 



Sulphuretoflead. . . 6-437 - 12-357 



99-983 99-959 

 15. Plagionite. — The crystals of this mineral belong to 

 the oblique rectangular prismatic system of Beudant. If we 

 consider the faces belonging to an octahedron for the 

 punvictur form, then the faces parallel to the plane of the 

 two axes are truncatures of the anterior angles. They are 

 implanted in quartz. Fracture conchoidal. G. Rose has 



