THE operation of refining base bullion may be divided into the following heads- 1. Softening. 2. Extracting the gold and silver from softened bullion. 3. Refining the desilverised lead from (2). 4. Liquation of gold and silver crusts obtained in operation (2). 5. Retorting the residue from (4). 6. Concentrating and refining bullion from (5). 7. Parting Dore bullion from (6). SOFTENING PROCESS.-- The end in view in this process is to remove all deleterious metals from the bullion. These undesirable impurities may be copper, arsenic, antimony, tin, tellurium, bismuth, sulphur, iron, etc. The elimination of these at the beginning of the process both cheapens and hastens the desilverising and de-aurumising I process, and they must also be extracted before the finished product of lead is fit for the, market as "Soft Lead," to be afterwards used in the manufacture of pipe, sheet, tea lead, etc.