624 On the native method of Refining [Dec. 



The refiners are in total ignorance of the rationale of this process, 

 and I regret that I can only conjecture it, being unacquainted with the 

 matters most commonly combined with the gold of Bhote, or forming 

 its matrices. 



Note to the above paper. By J. P. 

 The process described by Dr. Campbell is precisely that employed 

 throughout India, and no where more frequently than in Calcutta. 

 I took occasion myself to notice it in the Oriental Magazine for June 

 1827, for the purpose of pointing out a material error in many 

 manuscript copies, as well as in the English translation, of Abul Fazl's 

 description of the same operation. As the passage alluded is short, 

 and the work containing it, now out of print, I venture to subjoin the 

 passage: 



" In Gladwin's translation of the Ayeen Akbery, there is an account of the 

 native process for refining gold, in which it is mentioned, that a composition 

 of ' equal parts of saltpetre and brick-dust' is spread between the plates of gold, 

 which are then heated red hot, &c. 



" As it is well known to chemists, that the ignition of such a mixture would 

 only diseugage nitric acid, the very acid which is actually used in the Euro- 

 pean method of refinage in the humid way, this passage is calculated to mislead 

 even the scientific reader. The mixture really used by the native refiners is 

 composed of equal parts of common salt (muriate of soda) and brick-dust, just 

 in the same way as is practised in Europe, in what is termed the dry method of 

 refinage. The rationale of the process is, that muriatic acid has the power of 

 dissolving silver and copper at a red heat, and the muriates, being volatile, quit 

 the surface of the gold plate as soon as they are formed, giving place to a fresh 

 action from further acid, until the gold is rendered perfectly pure. The mu- 

 riate of silver is not decomposed, unless some free alkali be present. Now, the 

 nitric acid will quit all its bases at a red heat, and is itself incapable of acting 

 upon silver at that temperature, although it will assist in oxydating copper and 

 other metals : saltpetre is indeed frequently used in purifying silver. There is 

 then evidently some mistake, and if so, is it attributable to the translation ? or to 

 the original work, which is so accurate and particular in most of its details ? For 

 the purpose of deciding this question, several old manuscript copies of the Ayeen 

 Akbery were examined. In one the expression was simply shoreh, which 

 agreed with the translation. In another it was shoreh i hhist kh&m, the 

 saltpetre q/half-burnt bricks : — at last, in an older manuscript, the true original 

 reading was discovered, which proved to be nimak shoreh, coarse bitter com- 

 mon salt, such as is given to cattle. The ignorance of copyists had ima- 

 gined perhaps that the word nimak was redundant, mistaking shoreh for 

 a substantive, as though it were written " salt of saltpetre," and nimak was there- 

 fore henceforward omitted. The ease with which the sense of passages in manu- 

 scripts may become varied is further evinced by the second example, where the 

 original plain sentence of ' half of coarse salt, and half brick-dust,' has suffered 

 two metamorphoses, and appears as merely ' the nitre of half-burned bricks ! 



" Perhaps in this place, a brief account of the whole process will not be 

 devoid of interest. 



