SMELTING OF CUPREOUS PYRITES. 53 



Sometime afterward Mr. Giieniveau examined a sped- Another spe- 

 men of scoriae of the first kind, obtained in like manner from anTr"edfo/* 

 the fusion of the ore, which was in the collection of the Coup- manganese 

 cil of Mines. His principal objects were to ascertain whe- ^ru^^^.^'g^^" 

 ther it contained manganese, and wliether the insoluble r€- 

 siduum had a mixture of sulphate of barytes : but as the 

 component parts of this specimen ditfered from those of the 

 former, he gives the following account of his analysis. 



He treated 5 gram. [77g»*s.] of the scorire, thoroughly pul- Analysis, 

 verised, with ten of caustic potash, in a silver crucible. The 

 fusion was complete ; and on its being sufiTered to grow 

 cold, and a large quantity of water being added, no 

 green colour appeared, which evinced, that no manganese No manganese, 

 was present. 



Another portion he treated with concentrated muriatic Examined for 

 a<4d mixed with a little nitric, to detect the alkalis. Having; ^^^^^^^* 

 separated the insoluble residuum, he treated the solution with 

 ammonia, which separated a part of the earths and metals. 

 The copper and zinc dissolved were then precipitated by 

 sulphuretted hidrogen; the excess of this gas >\as expelled 

 by ebullition; the lime was thrown down by oxalate of am- 

 njonigi ; and the liquor was evaporated to dryness. The am- 

 monlacal salts were then driven off by bringing the residuum 

 to a red heat in a platina crucible, and a pretty considerable 

 quantity of fixed salts remained. Having dissolved these in 

 a very small quantity of water, he added to the solution mu- 

 riate of platina, which occasioned no precipitate ; and en- 

 deavoured, but in vain, to obtain crystals by cautious eva- 

 poration and cooling; which convinced him, that neither Neither potash 

 potash nor soda was present. nor soda. 



13y various trials he found, that the fixed residuum con- Barytes and 

 sisted of the muriates of barytes and magnesia. magnesia. 



Lead too was an object of his particular research ; but he j^q je^^j 

 could not discover an atom. 



scorlvB make with sulphuric acid a little concentrated, and with dilute 

 muriatic acid ; an effervescence owing to the decomposition of water, 

 since the gas has the smell of hidrogen set tree by iron. The same phe- 

 nomenon has been observed in scoriie from sparry iron ores, which were 

 not attractable by the magnet, and contained a great deal of manganese, 

 and but little iron.' " . 



From 



