350 Dr. Vest on Vestium. [May, 
no means a characteristic property of that metal, as I formerly 
imagined ; but belongs equally to other metals with which 
vestium seems readily to associate. The precipitate of nickel 
and cobalt, by means of sulphuretted hydrogen, are easily dis- 
tinguished from each other. The former is quite black, and 
swims about in a diluted solution, like fine soot, in soft 
particles. The precipitate in a diluted cobalt solution is reddish- 
brown, like that of vestium, and the solution resembles a strong 
infusion of coffee. 
4. Pure ammonia precipitates vestium; but an excess of that 
liquid redissolves the precipitate, and the solution is colourless. 
The colourless appearance of this solution distinguishes 
vestium from nickel and cobalt. However, as by very great 
dilution we may obtain colourless solutions of both those metals, 
the proof is only of weight when we attend to the concentration 
ofthe liquids. Ifthe vesttumsolution be very much concentrated, it 
assumes a yellowish tinge with ammonia ; and if nickel be present, 
it assumes a greenish tinge ; but it never becomes blue. I long 
ascribed this colour to the presence of iron ; but I now believe 
that my opinion was erroneous, and that yestium itself, when 
very concentrated, has the property of tinging ammonia yellow. 
5. Carbonate of ammonia throws down from muriate of yes- 
tium, even when it contains an excess of caustic ammonia, a 
snow-white powder. This powder does not become coloured, 
either by agitation or by longer digestion ; nor does any sensible 
change take place in the liquid; but some oxide of vestium is 
dissolved which is only partially precipitated by rest or evapo- 
ration, but completely when carbonate of potash is added and 
the liquid evaporated. 
Carbonate of ammonia scarcely occasions any precipitation in 
sulphate of vestium. Oxalate of ammonia precipitates the dis- 
solved vestium from none of those solutions in carbonate of 
ammonia. 
The phenomena exhibited by the sulphuric acid solution have 
some resemblance to those exhibited by lime ; but the solubility 
of the oxide of vestium in carbonate of ammonia completely 
destroys the similarity. We see that vestium cannot be com- 
pletely precipitated from its solutions by carbonate of ammonia, 
and not at all from its solution in sulphuric acid. Indeed, if 
we employ a very considerable quantity of the carbonate of 
ammonia, we may obtain a complete solution of the vestium ; 
and solutions of vestium may in this way be examined. 
6. Carbonates of potash and soda precipitate the vestium in 
the state of a carbonate ; but the alkali retains a portion in solu- 
tion, which is in part precipitated by boiling. If the ley 
be crystallized, crystals are frequently obtained’ containing 
vestium. 
7. Lime-water precipitates the vestiuna in light-white flock 
provided there be no ammonia in the solution. Sulphurette 
