VOL. XXXIX.] PHILOSOPHICAL TRANSACTIONS. ' QS 



An amalgam of tin and quicksilver in the same proportions (viz. 1 oz. of 

 tin and 3 oz. of quicksilver) being digested in the same degree of heat, and 

 afterwards subjected to distillation ; there passed over into the receiver '2 oz. 

 4 drs. of quicksilver. There remained behind in the retort a powder, the finer 

 part of which consisted of fixed mercury,* and the coarser black portion of 

 particles resembling tin. There adhered to the neck of the retort a small 

 quantity of quicksilver, weighing 2 drs. 5 grs. The residuary mass of tin 

 weighed 1 oz. 1 dr. g grs. There was a loss of 46 grs. This experiment 

 shows that quicksilver cannot be extracted from tin; but more than a seventh 

 part of the quicksilver remained combined with and fixed in the tin, even 

 when subjected to a red heat for the space of 4 hours. — Dr. B. mentions that 

 the quicksilver distilled from the lead and tin amalgams, on being shaken in a 

 clean white glazed earthen vessel soon deposited a black stain on the sides of 

 the vessel : that on being spread out on writing paper, the said quicksilver left 

 a black trace where it passed over the paper ; and lastly, tiiat when at rest, 

 the surface of such quicksilver was always covered with a greasy pellicle or film. 

 Hence he supposes, that some of the particles of these metals may be volati- 

 lized by the quicksilver; but this he observes is very different from the actual 

 conversion (as some have supposed) of a portion of these metals into quick- 

 silver. 



The results of Dr. B.'s experiments on amalgams of gold and quicksilver, are 

 related in the 3d part of his communications on this subject. After subjecting 

 an amalgam of gold and quicksilver to digestion and repeated distillations,-|- 

 the gold was found to be of the same weight, and to possess the same proper 

 ties as it did before it underwent this treatment. The quicksilver was in part 

 converted into a very fine brown powder, of a sharp metallic taste, which how- 

 ever was again brought to the state of fluid quicksilver, by the action of a 

 stronger degree of heat. Thus there was no purification of the quicksilver by 

 the gold in this experiment, the latter metal being found unaltered after the 

 operation. 



When an amalgam of gold and quicksilver is exposed to the fire, the silvery 

 appearance of the amalgam is changed first into a brown, and afterwards into 

 a black colour ; but by the action of a higher degree of heat, the yellovy 

 colour is restored to the gold, and the silvery lustre to the quicksilver. From 

 these experiments it is inferred, that all hopes of fixing quicksilver by subject- 

 ing it to the action of the fire with gold, must be relinquished for ever. 



• i. e. not volatile in the beforementioned degi-ee of heat, 

 t In the course of these experiments, the distillations were repeated 877 times ! 



