12 LAWSON ON THE IMPROVEMENTS IN AMALGAMATION. 



to the purpose of gold amalgamation. The Doctor here explained 

 the ordinary process of separating the gold from the quartz, by 

 using mercury alone, a process which was often inefficient, owing to 

 the presence of sulphides, which, coating the gold, prevented the 

 action of the mercury upon it. It was found by Mr. Crooke, that 

 by combining the sodium with mercury, an amalgam was formed that 

 had much greater power of taking up gold than mercuiy alone. By 

 means of a sand bath and a glass vessel, the experiment of combin- 

 ing the mercury and sodium was shown to the meeting, and a con- 

 siderable piece of amalgam made with the requisite proportions of 

 mercury and sodium ; and the action of the amalgam so made was 

 shown on thin slips of gold freshly annealed, from the Waverley 

 mines. It Avas shown that these slips of gold were not at all affected 

 when drawn through ordinary mercury ; but the moment they 

 came into contact, however slight with mercury to which some of 

 the sodium amalgam had been added, they were completely and 

 permanently coated with mercury. The following was the account 

 given of Mr. Crooke's process, which had been fully investigated 

 by an extensive series of experiments in Professor Lawson's labor- 

 atory, and so favourably reported upon that a patent has been 

 granted : — 



" This invention relates to certain improvements in the method 

 of treating the ores or substances containing gold and silver by amal- 

 gamation, and whereby those metals can be more perfectly and 

 completely extracted and separated therefrom, than by the processes 

 hitherto adopted. A solid amalgam of sodium is in the first place 

 formed by combining about one part of sodium with about thirty 

 parts by weight of mercury. The solid amalgam thus formed is 

 then added to the mercury employed for the purposes of amalgama- 

 tion, the proportions varying according to the quantity of metal 

 contained anct the state in which it occurs in the ore or matrix. If 

 however, the proportion of the alkali metal exceeds that of one part 

 to from 120 to 150 parts of mercury, the amalgam becomes viscid 

 and its manipulation inconvenient. The effect of thus combining 

 the sodium with the mercury, is to impart to the latter a greater 

 affinity for or power of adhesion to the metal under treatment, than 

 it possesses in its simple and uncombined condition. Instead of 

 using the solid amalgam as hereinbefore mentioned, the sodium may 



