specific Gravity , and comparative W ?ar of Gold. 53 
almost as soon as a portion of the arsenic had united with the 
gold ; and the whole surface of the plate, therefore, remained 
thinly coated with arsenicated gold, by which, a certain degree 
of rigidity was produced. 
These experiments prove, that arsenic, in the state of vapour, 
will readily combine with gold, even when the latter is only 
raised to a common red heat. But the whole substance of the 
gold is not, in this case, immediately and completely pervaded 
by the arsenic ; for it appears, that the combination of these 
two metals, being extremely fusible, immediately flows, and is 
separated from the remaining part of the mass of gold, pro- 
vided that the original degree of heat be not very speedily 
checked; but, when this happens, the mass or plate of gold 
remains coated with the arsenicated compound. 
The effects which (according to these experiments) metallic 
arsenic appears to produce upon gold in a red heat, may in a 
great measure be compared to those which are observed when 
sulphur, or phosphorus, is combined with various metallic 
substances. 
GOLD ALLOYED WITH ANTIMONY. 
Experiment 1. 
To eleven ounces one pennyweight and three grains of gold, 
23 car. 3-jgrs. fine, in perfect fusion, eighteen pennyweights 
and twenty-one grains of pure antimony were added, and, being 
well mixed, the whole was poured into a mould of iron. 
This mixture had in some degree acted upon the surface 
of the mould ; for it was with difficulty that the bar could be 
