500 Gold alloyed with Rhodinm. 
were not all brilliant, I did not mix it with the former pre~ 
duct; but, on reflection, I thought it might be owing to the 
want of heat, and that I ought to add it, as well as that dis- 
solved by the potash. 
i. 
From the other three fourths of the solution, the greater 
part of the acid was distilled, and what remained was satura- 
ted with muriate of ammonia without excess. The orange- 
coloured precipitate lost its redness by time, and changed in- 
to an ochre-yellow ; for which reason, and because on wash- 
ing it with hot water, it became greenish, I inferred, that 
although it detonated like fulminating gold, it was not pure- 
n fact; having melted 10 grains with borax, afier having 
been infused in oil, a white button* came forth, which was 
quite rough, and in the interior, where it was observed to be 
uneven, it had the colour of whitish copper or nickel, leaving 
oria of a leek-green, and cochineal-red coloar, an 
weighing 5.9 grains. The white surface changed after a 
while, to pinchbeck-gray, and having fused it with nitre, it 
yielded a globule of pure gold,+ which weighed 4.3 grains. 
her 10 grains being fused, another button was obtained, 
which was also without ductility, leaving a scoria of a bright- 
er red, and which weighed 7.1 grains; and being melted in 
the same way as before, afforded another globule of the 
same weight as the other, viz. 4.3. Now then, if 100 of 
ummoniuret yield 43 of gold, 212, whiclr was the weight of 
amounting to 38.6 per-cent. of alloy, _ The sp. gr. of this 
alloy should be 15.91, but being only 15.40, it follows that | 
there is an augmentation, 
she remaining solution was distilled to dryness, and @ 
—— vy residuum remained, which, treated with muriatic 
acid, did not exhibit the variations of colour, shown by iridi- 
um ; nor with muriate of ammonia did it yield red crystals, 
Eb . ; oe 
‘ihn — of this metal to appear at the surface of the gold, is very 
+ I attributed the purity of these globules t i 
bet ; : se g © th the bot- 
tom and sides of the crucibles having been gatalanad pene S Tease ; 
the tendency of this to vitrify the rhogium is singular. 
