354 Dr. Vest on Vestium. '.. Giaa, 
another substance, which formed white flocks, and did not 
communicate any colour to borax (therefore vestium). 
I dissolved a portion of the impure regulus, first obtained from 
the ore in nitric acid, and without freeing it from the arsenic, I 
precipitated by potash. The precipitate was dissolved in sul- 
huric acid, sulphate of potash was added, and the liquid was 
Eriiohit to the degree of concentration requisite to yield crystals. 
The nickel crystals were at first, as was usually the case, very 
light green ; but by repeated solutions and crystallizations, they 
became darker and darker, because more of the white oxide of 
vestium was separated every time it was crystallized. The white 
flocks obtained by all these processes | mixed with sulphate of 
potash, and again evaporated to separate the nickel still more 
completely. 1 then digested it with sulphate of potash, filtered, 
and reduced the oxide in a good wind furnace with common salt 
and charcoal. The regulus which I obtained had a very fine 
granular fracture, was very brittle, and its fracture showed a very 
white colour. . By exposure to the air, it soon lost its lustre. 
I dissolved a portion of this regulus in nitro-muriatic acid, and 
decomposed a portion of this green solution (for nickel has a 
very strong colouring power upon acids) by potash. I dissolved 
the white precipitate in sulphuric acid, added a portion of sul- 
phate of potash, in order to separate the nickel by crystallization, 
and washed the salt formed in cold water. The white flocks, 
which rendered the solution muddy, were separated, and decom- 
posed by carbonate of ammonia added in excess. By this 
means | obtaimed a fine white precipitate; and the ammonia 
was but slightly coloured. Thus I procured vestium merely 
in combination with arsenic (for that metal had not been sepa- 
rated).* 
The iron is sometimes of very difficult separation, sometimes 
it is easily got rid of. This diversity seems to depend upon the 
difterent portions of iron contained in the ore under examination. 
One portion of the vestium may be easily purified, by dissolv- 
ing the carbonate in nitro-muriatic acid, evaporating to dryness, 
and washing the dry mass with water. The dry residue (submu- 
riate of vestium) is tolerably pure, or at least may be made so 
by a second evaporation with muriatic acid. But a great deal 
of vestium remains in the solution along with iron, nickel, and 
cobalt. These experiments are not always equally successful. 
The solution may contain arsenic or not: when the arsenic is 
entirely removed, the oxide of vestium cannot be reduced tothe . 
metallic state. . 
I tried to decompose by carbonate of potash a solution of the 
impure regulus, after | had mixed it with sal ammoniac. The 
solution was at first blue from the nickel which it contained ; but 
it soon changed into green. A white precipitate fell, which 
* Another time T precipitated the solution by acetate of lead, expecting in vain 
to separate thearsenic by that way and get the vestium pure. 
