Analysis of Iron Ores, &c. 13 



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

 of lime, were found in the solution. 



From these two analyses it appears, that the fluors ana- 

 lysed consist almost wholly of calcareous matter, but that 

 or Pesme is the most pure. They show at the same tune, 

 that the stones examined contain a small quantity of phos- 

 phate of lime, which certainly does not amount to a five- 

 hundredth part. 



II. Analysis of the Scoria? of the Iron Works at Dramhon. 

 M* Vauqueiin began with these scoriae, rather than with 

 the ores and smeltings, because these scoriae include more' 

 foreign matters in a smaller bulk. 



They have a shining blackish colour, nearly resembling 

 some 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 laminar. 

 Five grammes (77 grains) of scoria?, fused twice in suc- 

 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 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 scoriae thus treated were put 

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

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

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

 which, when collected, washed, and dried, weighed two 

 decig. (three grains) amounting to four per cent — The al- 

 kaline liquor, freed from the manganese and filtered, still 

 retained an orange yellow colour, which led M. Vauqueiin 

 to suspect the presence of chrome. 



To verify this suspicion, it was necessary, in order to 

 facilitate the operations requisite for detecting the chrome, 

 to separate the alumine and silex, that were in the alkaline 

 lixivium : and to avoid the presence of muriatic acid, which 

 would have thwarted the end he proposed, M. Vauqueiin 



employed 



