34 M. Bonsdorff on the [July, 



Experiments to separate Antimony from Silver by Cupellation. 



Of this alloy, which was so formed as to contain about 31 

 per cent, of antimony, and which in its fracture and aspect per- 

 fectly resembled the regulus obtained from red silver ore, 0-738 

 gr. was placed in a bone-earth cupel, which was introduced into 

 a red-hot muffle in a cupellating furnace. The heat in the muffle 

 was increased by means of an air tube introduced into the 

 muffle through a piece of charcoal placed in its mouth. The 

 antimony was speedily driven off, and in great quantity; and 

 when on increasing the heat, and blowing on the cupel with a 

 bellows, no more antimonial fumes appeared, the silver regulus 

 was withdrawn, and found to weigh 0512 gr. It was ductile, 

 and on the surface dull and greyish, showing that it was not 

 quite free from antimony. It was, therefore, enveloped in five 

 times its weight of pure lead, and exposed to the usual cupellat- 

 ing process till it assumed the appearance of pure silver. The 

 regulus now obtained was silver-white, had a strong metallic 

 lustre, and weighed 0*507 gr. It amounted, therefore, to 68 

 per cent, of the antimonial alloy ; and the regulus first obtained 

 contained about 1 per cent, of antimony. An experiment was 

 made with another portion of the same alloy. It gave, after the 

 first process, a dull regulus, whose weight was very nearly in the 

 same proportion as in the experiment already described ; and 

 when it was dissolved in nitric acid, it left behind it a little oxide 

 of antimony. The pure regulus obtained in the first experi- 

 ment dissolved in that acid without leaving any residue what- 

 ever. 



After these preliminary trials, 0-511 gr. of the regulus 

 obtained from red silver ore was taken and treated in precisely 

 the same way. The first process gave a regulus weighing 

 0*375 gr. dull, and with a yellowish-grey colour on the surface ; 

 and when it was cupellated with Ave times its weight of lead, it 

 became silver-white and splendid, and weighed 0-370 gramme. 

 It dissolved in nitric acid without any residue whatever, and 

 gave with muriatic acid horn silver, weighing after fusion 0-490 

 gramme, equivalent to 0*369 silver, and thus corresponding very 

 nearly with the original weight of the regulus. According to 

 this experiment, the whole regulus, weighing T2255 gramme, 

 contained 0-8866 gramme silver, and the antimony driven off 

 weighed 0-3389 gramme. 



The matter which had passed into the tube E weighed, as has 

 been already mentioned, 0*011 gramme. The fragments of the 

 glass to which that grey metallic-looking substance adhered, 

 were digested in nitric acid, which dissolved a little sulphur, as 

 was evident from the action of muriate of barytes on the liquid. 

 What remained was dissolved in muriatic acid, and contained, 

 as far as so small a quantity of matter could be tested, nothing 



