History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s2.t3.22

v1.c13.s2.t3.22

“The pure and impure silver may be heated four times with CuSO₄, mixed with powdered bone (*Astithutha*), again four times with equal quantity of lead and again four times with CuSO₄ (*Suskatutha*), again three times in a skull and lastly twice in cow dung. Thus purified silver is obtained. This process has been also quoted by Ray (1956) and Bhardwaj (1979). Bhardwaj (1979) has written that this process of cupellation for the production of Silver and Lead was well developed in the 2nd half of 3rd M.B.C.