Copper in Ancient India c11.s2.11

c11.s2.11

In later times copper sulphate appears to have also been prepared by the action of sulphuric acid (dāha-jala, lit, burning water) on metallic copper. We find the following recipe in the alchemical work Dhātukriyā (16th century)--"tuttham (blue vitriol) is obtained by the action of sulphuric acid on copper."¹ Sulphuric acid was obtained originally in the 13th century in India as an "essence of alum or green vitriol" by the distillation of these substances. The distillation of alum and green vitriol is described in Rasaratna-samuchchaya.² The word dāha-jala as an equivalent for sulphuric acid is evidently of later origin.³ This process of preparing copper sulphate by the action of sulphuric acid on copper was discovered in Europe by Glauber in 1648, so that India can claim priority in the matter of the discovery of this reaction by nearly a century.