ANALYSIS OF IRON ORES, &:C. 33 



sand, with a minute quantity of alumine and iron. The 

 solution, which is colourless, gives with ammonia a light, 

 flocculent, semitranspa.eut, yellowish white precipitate, in 

 which was recognized the presence of iron, a little alumine, 

 and phosphate of lime. It likewise contained some traces 

 of silex. 



The spar of Pesme is compact, of a grayish white, and That at Pesme, 

 dissolves in nitric acid, leaving a residuum of about a twen- 

 tieth of its weight. A little iron, alumine, and phosphate 

 of lime, were observed in the solution. 



From these two analyses it appears, that the fluors anar Almost wholly 

 lysed consist almost wholly of calcareous matter, but that ["h^rof^pe^me* 

 of Pesme is much the most pure. They show at the same most pure. 

 time, that the stones examined contain a small quantity of 

 phosphate of lime, which certainly does not amount to a five 

 hundredth part. 



II. Analysis of the scorice of the iron works at Drambon, 



Mr. Vauquelin begins with a chemical examination of Scoriae of 

 these scoriae, rather than with that of the ores and smelt- I^f^'^l^on. 

 ings, because these scorite include more foreign matters in a 

 smaller bulk. 



They have a shining blackish colour, nearly resembling Physical cha- 

 certain oxides of manganese. Their weight indicates, that ^'^^^^^^' 

 a considerable quantity of metallic matter is left in them. 

 Some parts exhibit blebs of different sizes, others are com- 

 pact. Their fracture is crystallized, either needly or lami- 

 nar. 



Five grammes [77 grains] of scorioe, fused twice in sue- Analysed. 

 cession with an equal weight of caustic potash, communi- 

 cated to the alkali a very deep green colour, when the mass 

 had been washed with water. 



This green colour is known to be an unequivocal proof of Manganese, 

 the presence of manganese, and it is the best method we can 

 employ, to discover the slightest trace of this metal in any 

 substance. 



All the washings of the sconce thus treated were added This separated, 

 together, and boiled, to separate the manganese. In pro- 

 portion as this effect took place, the liquor lost its green 

 colour, and the metal floated in it in the form of brown 



Vol. XXI—Sept. 1808, D flocks, 



