55* Intelligence and Miscellaneous Articles. 



pelopic acids recently discovered by M. Rose in the columbiferous mi- 

 nerals of Bavaria and America. The columbite of Limoges is denser 

 than these, of which the former has a density of 6* 390, 6*078, 5'976, 

 and the latter of 5*708, 5*495. That of Tamela in Finland, which 

 M. Rose considers as pure columbic acid, is of density, 7*197, 7*476, 

 7*510. — Annates des Mines, tome xiii. 



ON ALLUAUDITE, — A NEW PHOSPHATE OF IRON, MANGANESE 

 AND SODA. BY M. A. DAMOUR. 



This substance was recently found imbedded in pigmatite near 

 Limoges. 



Its colour when viewed in mass is clove-brown ; its fracture is 

 laminated and shining, and in some parts, which seem to have un- 

 dergone some alteration, it is chatoyant like hyperstene. Fracture 

 indicates a right rectangular prism as its crystalline form. It 

 scratches fluor spar, and is scratched by a steel point ; the powder is 

 brownish -yellow. Its density is 3*468. 



Moderate-sized specimens appear occasionally to contain accidental 

 admixtures of peroxide of iron and black oxide of manganese : tbey 

 are sometimes associated with green phosphate (dufrenite) and blue 

 phosphate of iron. 



By the blowpipe, in platina forceps, this mineral fuses very readily 

 with intumescence, into a black globule, which is not magnetic ; in 

 the oxidizing flame, it dissolves entirely in phosphoric salt and indi- 

 cates manganese ; heated in a tube, it decrepitates and disengages a 

 small quantity of neutral water. 



When in fine powder it dissolves readily in cold hydrochloric acid; 

 the solution at first is of a blackish colour and evolves chlorine ; if the 

 temperature be raised to 140° F., the liquor becomes bright, and of 

 a brownish-yellow colour. Sulphuric acid diluted with four times 

 its bulk of water does not act upon it cold. At 212° F. it dissolves 

 slowly, and the solution is of a reddish-violet colour ; this colour 

 indicates manganese of a higher state of oxidizement than manga- 

 nous oxide, but it occurs only with the chatoyant portions of the 

 specimen. 



Nitric acid acts upon it with difficulty, but oxalic acid when heated 

 dissolves it completely ; when the solution is suffered to evaporate 

 spontaneously, granular crystals of oxalate of manganese and peroxa- 

 late of iron are deposited. 



By analysis this mineral yielded — 



Phosphoric acid 41*25 



Peroxide of iron 25*62 



Protoxide of manganese . . 23*08 

 Peroxide of manganese .. 1*06 



Soda 5*47 



Silica 0*60 



Water 2*65 



99*73 

 M. Damour proposes the name of alluaudite for this mineral, in 

 honour of M. Alluaud, well-known for attachment to the sciences. 

 — Ibid. 



