A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c18.s8.6

v1.c18.s8.6

The third process of the *jamakwala* is the main step in the reduction of gold. He scoops out on the earth in an open place a hollow of the shape of a hemisphere about a foot in diameter, and having thoroughly smoothed the interior of this hollow, he covers it with a layer of slaked lime about half an inch thick. After the lime has dried, it presents the appearance of a course white china vessel, imbedded in the earth. In this the balls prepared by the second process are placed. The *jamakwala* then forms a powerful charcoal fire over it and with two or three large pairs of bellows causes the flame to play on the mass below. The lead of the *poonoor* is soon reduced and dissolves, as it were, the reduced gold, silver and copper. A large metallic mass thus collects at the bottom of the hollow, consisting mainly of lead. The blowing is now continued as hard as possible from above and the metal being oxidised to litharge begins to be blown off. The process must be continued till the whole of the lead has passed off and a mixture of gold, silver and copper remains behind. Care should always be taken in this operation to see that the last trace of lead is thoroughly got rid of; for nothing affects so much the ductility and malleability—virtues most important for the purposes of the goldsmith—of gold as a mixture ever so little of lead. Thus "one two-thousandth part renders the metal too brittle for rolling and its very fumes produce a serious effect upon it."'¹