DESCRIPTION OF A NEW PROCESS OF REFINING. 7 \ 



to thofe obtained by the original proceffes, and it is thus that 



we daily fee a multitude of the arts arrive at a great degree 



of perfection. I might produce as examples, the art of the Inftances. 



pin-makers, that of the needle-maker, &c. &c. but I mean at 



prefent to confine myfelf to a new procefs for refining *, the 



details of which will fufficiently illuftrate what I advance. 



It is known in commerce, that articles of gold and lilver, Standard of 



after long ufe upon a change of fafliion, or from other circum- meted P ate 



° o . uncertain, 



fiances, are melted together without attending to any rule or 



proportion but that which arifes from the variable courfe of 



trade. 



The ingots obtained in thefe operations raufl, therefore, at 

 firft, contain different proportions of gold and lilver, but they 

 muft at laft be united with thofe metals, which in conformity 

 to the law will require to be added, in order to their employ- 

 ment in the arts of the jeweller and the iilverfmith. 



To bring thefe metallic compounds into circulation again, Method of 

 that is to fay, to qualify them to be reconverted into works of bnn § in g metal* 

 gold or lilver, they muii undergo an operation which reduces ftandard, 

 them to the ftandard prefcribed by law, there are two methods 

 of accomplifhing this end. 



The firll and molt natural is that which points out theaddU 

 tion of the quantity of gold, lilver, or copper, necefTary to 

 rellore the fixed proportions of the alloy. 



In the fecond all the metals are feparated from each other, 

 and after reducing them to the Irate of pure or limple bodies, 

 the alloy is formed according to the legal proportions, but the 

 firft of thefe procefles conftitutes part of the fecond, inafmuch 

 as it employs the fame materials as are purified by means of 

 this laft, which is ufed to feparate an alloy of gold, lilver, &c. 



It is to this operation that the name of refining is given. 



All the operations of refining are founded upon the peculiar Refining pro- 

 properties of thofe bodies on which the refiner is to work. The P erl y fo called * 

 chief procefs is that which bears the name of parting; its bafis Partin 2* 

 is the infolubility of gold in the nitric acid ; this acid, by dif- 

 folving the filver and copper, leaves the gold, which was al- 

 loyed with thefe metals, at the bottom of the velfel in which 

 the folution is carried on. 



* I here fpeak of refining as an art, without reference to its con- 

 nection with the financial operations of the ftate. 



This 



