1819.} Dr. Vest on Vestium. 353 
hard, vesicular body with an earthy fracture, which was a fused 
mixture of sulphuret of potash and oxide of vestium. 
The regulus, being dissolved in nitric acid and evaporated to 
dryness, gave a yellowish powder. his powder being boiled in 
muriatic acid dissolved with difficulty, and formed a yellow- 
coloured liquid, which contained iron, although I had not 
observed the presence of that metal before the reduction. The 
liquid was precipitated by carbonate of ammonia ; along with the 
iron there fell a good deal of white, slimy carbonate of vestium. 
The ammonia was bluish. Vestium, over which nitric acid is 
boiled to dryness, becomes with difficulty soluble in acids, and 
seems to be converted into another oxide. 
A portion of the regulus, which I dissolved in nitro-muriatic 
acid and precipitated by caustic ammonia, gave me a rose red 
solution, and oxide of iron remained on the filter. When the 
red solution was evaporated, there remained a white residuum 
coloured by cobalt, which was not again completely soluble, but 
left a white matter tinged slightly red hy cobalt. This residue 
being separated from the solution, it was dissolved in muriatic 
acid, evaporated till white flocks fell, which were separated from 
the cobalt solution by decantation. These white flocks became 
brown when treated with sulphuretted hydrogen water. The 
oxide of vestium could not be precipitated from the ammoniacal 
‘solution by carbonate of potash ; probably because the excess of 
ammonia prevented the precipitate from appearing. 
I boiled the white flocks, separated from the green nickel 
crystals by decantation, in muriatic acid, filtered, and decom- 
posed the clear solution by means of caustic ammonia. The 
ammoniacal solution was greenish. Carbonate of potash being 
dropped into it, a white precipitate fell, which I collected ona 
filter and washed. I evaporated the ammoniacal solution, 
poured sulphuric acid into it, and set it aside to crystallize, in 
order to obtain the oxide of vestium which it still contained. 
The precipitate on the filter, when dried, was a fine white 
powder with a shade of blue. It, therefore, contained cobalt 
which had been precipitated from the ammoniacal solution by 
the potash. I rubbed this powder with an equal volume of white 
arsenic, and with four times as much black flux, put it into a 
crucible, and exposed it to the temperature of 70° Wedgewood 
for an hour. I obtained a metallic button. On dissolving this 
button in nitro-muriatic acid and evaporating the solution, there 
remained a reddish crust of arseniate of cobalt. I softened it 
with water, digested it for some hours in muriatic acid, and then 
washed it out. There now remained behind a white gelatinous 
mass, which, being fused with borax, communicated no colour.* 
It thus appears that there was in the regulus, besides the cobalt, 
* When strongly concentrated, vestium gelatinizes in acid solutions It must be 
dried by exposure to heat. 
Vou. XIII. N° V. Z 
