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XII. Method of filling up Engraving on Silver with a 

 mdurable Black Enamel, as praclifed in Perjia and India. 



Communicated in a Letter from Siberia to Profeffor PaLLAS. 



From Neue Nordifche Beytrage, Vol. V. 



A AM now acquainted with the fecret of our filverfmiths 

 for filling up the engraving in plate with a black, glaffy, 

 durable mafs, refpecling which we have fo often converted^ 

 and it is very Angular that the Ruffians muft have derived 

 this procefs from the Perfians and the Indians. 



They take half an ounce of filver, 2~ ounces of copper, 

 3' ounces of lead, 12 ounces of fulphur, and n\ ounces of 

 fal ammoniac. The metals are melted together and poured 

 into a crucible, which has been before filled with pulverifed 

 fulphur made into a pafte by means of water ; the crucible is 

 then immediately covered that the fulphur may not take fire, 

 and this regulus is calcined over a fmelting fire until the 

 fuperfluous fulphur be burnt away. This regulus is then 

 coarfely pounded, and, with a folution of fal ammoniac, 

 formed into a pafte, which is rubbed into the engraving on 

 filver plate. The filver is then wiped clean, and fuffered to 

 become fo hot under the muffle, that the fubftance rubbed 

 into the ftrokes of the engraving melts and adheres to the 

 metal. The filver is afterwards wetted with the folution of 

 fal ammoniac, and again placed under the muffle till it 

 becomes red hot. The engraved furface may then be 

 fmoothed and polifhed without any danger of the black 

 fubftance, which is an artificial kind of filver ore (fablerz), 

 either dropping out or decaying. In this manner is all the 

 filver plate brought from Ruffia ornamented with black en- 

 graved figures, &c. 



Dd 3 XIII. Dif- 



