74 LAVvSON ON THE IMPROVEMENTS IN AMALGAMATION. 



the latter metals are soiled by grease or other extraneous matter. 

 Although he prefers that the amalgamation shall be conducted in 

 the presence of water, as in the usual processes, the operation, if 

 deshable, may be performed in a dry manner. The amalgam above 

 mentioned should be stored in air-tight vessels, or under naphtha, 

 such as metallic sodium is usually kept in. Instead of using the 

 amalgam as hereinbefore mentioned, the sodium may be combined 

 directly with the mercury employed, care being taken that the pro- 

 portions shall remain substantially as already indicated. 



" This invention can be used in conjunction with any machine -or 

 apparatus for performing the amalgamating process, and, in cases 

 where amalgamating vessels, or receptacles or places constructed of 

 iron or other metal are employed, an additional advantage arises 

 from the fact that the mercury combined as before mentioned with 

 sodium forms a thin film over the surface of the iron or other 

 metal, thus aiding in the collection of any minute quantities of the 

 precious metal under treatment. The subsequent extraction of the 

 gold or silver from the mercury may be conducted in any desira- 

 ble manner. It is not found in actual practice that a small quan- 

 tity of sodium, if accidentally allowed to remain in the mixtui'e 

 with the gold or silver and mercury, affects the subsequent treat- 

 ment in any appreciable degree. In cases where, from the nature 

 of the ores or substances under treatment, the mercury used for 

 amalgamation becomes divided into minute globules, technically 

 known as " flouring " or " granulating," there is frequently a diffi- 

 culty in separating the globules from the heavy particles of the 

 powdered ore or substances containing the precious metal ; the 

 addition of the sodium amalgam to such a mixture is found to 

 induce the coalescence of the liquid or viscid metallic particles, so 

 that a mechanical separation of the gold or silver amalgam from 

 the gangue may be readily effected. The employment of sodium 

 in combination with mercury will especially be found beneficial in 

 cases where gold or silver occurs with pyrites, sulphurets or minerals 

 containmg arsenic, antimony, tellurium, or bismuth. The process 

 of amalgamation with ordinary mercury is difficult to perfonn in 

 the presence of svich minerals without great loss both of mercury 

 and of the precious metal under treatment, owing to the surfaces of 

 the latter beinsr in such a tarnished or soiled state that mcrcurv 



