J54 Exfraels from the third Volume of 



amianthus. They have for matrix crystals of galena, to 

 which they slightly adhere. 



They exhibit the same phaenomena with the blowpipe as 

 white oxido of antimony precipitated by an aqueous solu- 

 tion of muriate of antimony; which is also su!>ceptible of 

 crystallizing by rest, when slowly precipitated, by a small 

 quantity of water. 



J As this white oxide retains muriatic acid, M. Hacquet 

 presumed that this acid formed a- part also of the white ore 

 of antimony. But the aivalysis of M. Klaproth proves that 

 this ore is a pure oxide of antimonv v/ithout nun'iatic acid. 



Some crystaJri of this oxide are found also in very small 

 insulated tablets in the red fibrous ore of antimony of Brauns- 

 dorf, in Saxony. 



Analysis of the Olive Ore of Cornwall. 



The only ores of this arsenical copper, hitherto known, 

 are found in Cornwall. M. Klaproth, having obtained from 

 all the varieties of this ore the same results, except a fe*v 

 slight differences in the proportions, gives here only an ana- 

 lysis of the Carrarac arsenical copper in needles. 



This ore, when exposed to the flame of the blowpipe, 

 detonates. White arsenical fumes are disengaged from it ; 

 and it fuses into a grayish red globule, which when fused 

 with borax gives a button of pure copper. Arsenical cop- 

 per contains 



, Oxide of copper 



Arsenic acid 

 Water of crystallization 



The foliated olive ore crystallized, in beautiful hexaedral 

 tablets, of an emerald green colour, of Tincroft, near Red- 

 ruth, had before been considered as muriate of copper, 

 M. Klaproth, however, has foimd it to be composed, like 

 the preceding, of copper and arsenic acid. He had not a 

 sufficient quantity of it to determine exactly the proportions 

 of its principles. 



It decrepitates speedily when heated on charcoal or in 

 a small crucible, and flies off in small scales; which must 

 be ascribed not only to the lamellated texture of its crystals, 

 but also to the great quantity of the water of crystallization 

 it contains, 



Arsenliiil 



