198 On the Decomposition of the Earths. [Marex, 
mixture supported in forceps made of slate. The metallic base 
of the earth was revived in such perfection that, after I] had 
placed it in nuftha, Professor Cumming compared it to platinum 
and to mercury. Mr. Holme also saw it often, and recognised the 
brilliant metallic appearance be had before witnessed, and which he 
has described in the Annals, vol. viii. As this metal retained its 
lustre unaltered for more than three weeks in maftha, it was taken 
out, and the mass containing it was placed in a covered platinum 
crucible, and left exposed for some days to the action of the air. 
At the end of this time all metallic lustre had disappeared ; but 
there remained some hard lumps of the earth within the crucible. 
Distilled water was then added, and the whole, falling into the 
pulverulent form, was collected upon a filter; proving to be no- 
thing more than pure larytic earth. 
2, Muriate of Rhodium.—A small quantity of this sal¢, of a red 
or rosy colour, had been given to me by the Rev. Archdeacon 
Wollaston, when Professor of Chemistry in this University ; having 
himself received it from his brother. Its purity, therefore, may be 
inferred. Being placed in a charcoal crucible, it admitted of easy 
fusion, attended with occasional combustion. The metal was then 
revived. It appeared at first black, externally, like the metallic 
slag of larytes. Upon being exposed again to the ignited gas it 
began to boil vehemently, and was partly volatilized. There then 
remained a brilliant globule of metal resembling the purest pla- 
tinum. This metal was malleable; but when much extended by a 
common hammer upon an anvil, it separated. By further conti- 
nuance of the heat it was entirely volatilized. I then repeated the 
experiment ; and again obtained the metal in a malleable state; in 
this state it was sent to Dr. Wollaston ; after being hammered. 
3. Brittle Regulus of Rhodium.—Having received some of this 
substance from Dr. Wollaston, I expected to render it malleable by 
the action of the ignited gas; but found it to be impracticable 5 
owing to some impurity with which it was combined, and which 
no degree of heat would totally expel. It appeared to be dissipated 
in white fumes; but these were owing to the volatilization of the 
metal; the residue, after fusion, being always brittle. 
I then endeavoured to purify it, by solution in the nifro-muriatic 
acid; using nearly Dr. Wollaston’s proportion of two parts of muriatic 
acid to one of nitric; and first fusing the rhodium with four times 
its weight of lead, by means of a common blow-pipe. The solu- 
tion was not entirely effected ; owing toa deficiency in the propor- 
tion between the two acids ; but being evaporated to dryness a salt 
was obtained which, after solution in alcohol, yielded a yellow pre- 
cipitate to pure ammonia. This precipitate when fused before the 
ignited gas became extremely malleable, but it was found to consist 
of rhodium still combined with lead. A further continuance of the 
heat, placing the compound upon charcoal, at length volatilized or 
vitrified the lead, and the rhodium was obtained in a malleable 
state. Professor Cumming, who, with Mr. Powell, and Mr, Holme; 
