4 9 
specific Gravity , and comparative Wear of Gold . 
2 dly. The remainder of the metallic arsenic coated the bot- 
tom of the inferior large crucible. 
3dly. On the sides of the upper crucible or dome were several 
small globules of gold. And, 
4thly. The button of gold in the small crucible, although 
unchanged in external appearance, was found to be extremely 
brittle, and, when broken, the fracture appeared of a coarse 
grain, and of a gray colour. 
The button weighed 481,5 grs. so that, exclusive of the gold 
which had been volatilized, there was an increase of the original 
weight, amounting to 1,5 gr. 
When arsenic is by any means combined with gold, it is not 
easy to separate it totally by mere heat; for, although this button 
was twice kept in strong fusion, during one hour each time, in 
an open crucible, it still retained some arsenic, and continued to 
be brittle. 
From this last experiment it is evident, that a considerable 
degree of affinity prevails between gold and arsenic ; but, as the 
latter is immediately volatilized at the instant of contact with 
melted gold, it cannot easily be combined with it when open 
vessels are employed, and when the arsenic is simply added to 
the gold in fusion, while so great a degree of heat is continued. 
This volatility of arsenic is, on the contrary, in favour of the 
combination when the operation is performed in close vessels ; 
for, as arsenic is reduced to a state of vapour by heat much 
inferior to that which is requisite to the fusion of gold, and as 
this vapour remains included during the melting and cooling of 
the gold, it necessarily follows, that the gold is cooled, and be- 
comes solid, while immersed in the arsenical atmosphere, so 
that the state of the gold, the extreme division of the arsenic, 
mdccciii. H 
