History of Chemistry in Ancient and Medieval India, Incorporating the History of Hindu Chemistry by Acharya Prafulla Chandra Ray c37.62

c37.62

As a result of the above treatments the articles acquire almost the beautiful yellow colour of pure gold: but the soldered surface appears at the same time as white as pure silver. This defect is then remedied by the next process to be described now. A mixture consisting of four parts of nitre, one part of common salt and one part of alum is added to water in an earthen pot. The amount of water used is such that about half the amount of salt mixture remains undissolved. The solution is then heated till it boils, evolving large quantities of gases and fumes, which obviously contain chlorine as a constituent. In this boiling solution the cleansed articles are kept immersed for a time, till a layer of shining gold is formed on the surface of the white solder, and the entire surface presents the appearance of being formed out of a homogeneous material. The articles are then taken out and washed. The reactions that occur during the above process may be explained as follows. When the salt mixture is boiled with water, chlorine and nitrosyl chloride are evolved. These act upon the gold forming a solution of gold chloride. The latter coming in contact with the white soldered surface deposits gold upon the latter, masking its white colour. It is clear that a considerable amount of gold is lost by solution in this treatment. The residual fluid, containing the dissolved gold and known as *jamak*, is, therefore, considered valuable and sold to a class of people called *jamakwalas*.