218 PARTING. 



operations, the gold is found to be deprived of much 

 of its usual ductility ; this however is easily re- 

 stored to it, by fusing it with nitre and borax. 

 The first part of this process is founded on a pro- 

 perty of sulphur, by which it is incapable of 

 uniting with gold, and is strongly disposed to unite 

 with all other metalUc substances, excepting pla- 

 tina and zinc ; and also upon the property of sul- 

 phur, that it has less affinity with regulus of anti- 

 moiiy than with any metallic substance with which 

 it can unite. Hence, when gold, alloyed with 

 ^Iver, copper, iron, lead, &c. is fused together with 

 sulphuret of antimony, these latter metals unite 

 witli the sulphur of the antimony, while the regu- 

 litm part, disengaged from them by its sulphur, 

 unites with the gold. 



The sulphur of the antimony, though it unites 

 with the baser metals, does not destroy them, but 

 forms with them a scoria, from which they may be 

 separated by treatment as an ore. 



Parting. 



When the quantity of silver united to the gold 

 is considerable, they may be separated by other 

 processes. Nitric acid, muriatic acid, and sulphur, 

 which cannot dissolve gold, attack silver very 

 easily ; and, therefore, these three agents furnish 

 methods of separating silver from gold, which 

 operation is called parting. 



Parting by nitric acid is the most convenient, 

 and, therefore, most used ; and is even almost the 

 only one employed by goldsmiths and coiners. 

 Wherefore it is called simply, parting. That made 

 with muriatic acid is only made by cementation, 

 and is known by the name oi' concentrated parting. 



