1807.] 
it exhaled a strong metallic odour, andin 
others assumed a more fixed form, they 
were led to regard it as a new metallic 
substance, the different properties of 
which they attributed to its different de- 
vrees of Oxygenation, 
During this same period, Mr. Tennant 
examined this black powder, and sue- 
ceeded in separating it lito two metals, 
one of which was fixed, and the other 
extremely volatile; while Wollaston, 
another British chemist, discovered that 
in the solution itself, which was supposed 
to contain only platina, there was a mix- 
ture of two other metals, which not only 
differed from those which ferm the black 
powder, but also from platina itself. 
Thus after having been subjected to a 
long series of the most accurate experi 
ments during the course of forty years, 
chemists have succeeded im detaching 
eleven different metals from this singular 
mineral, viz. platina, gold, silver, iron, 
copper, chrome, aud titaniie; the, two 
last were discovered by Fourcroy and 
Vauquelin, in the different coloured 
sands, which are always mixed with it. 
The two new metals separated from the 
solution of platina in the nitro-muriatic 
acid, by Mr. Wollaston, are: 
1. Palladium, a white ductile metal, 
heavier than silver, very fusible when 
united with sulphur, soluble m_ nitric 
acid, ‘colouring its solution of a beautiful 
red, precipitable in a metallic state by 
the sulphate of iron; yielding a dingy 
green precipitate with the prussiate of 
pot-ash, forming with soda a triple salt, 
soluble in alcohol. 
2. Rhodium, a grey metal, easily re- 
ducible, fixed and infusible, imparting a 
rose colour to its solutions in acids, which 
is rendered much deeper by the addition 
of muriate of tin, precipitated by the 
alkalies of a yellow colour, but not at all 
by the prussiate of pot ash, the triple salt 
of which with soda is insoluble in alcohol. 
M. Cuvier concludes this part of Ins 
report by observing, that-the two metals 
discovered by Mr. Tennant in the black 
powder after solution are: 
1. Iridium, a very hard white metal 
difficult of fusion, nearly insoluble in the 
nitro-muridtic acid, and wholly so in all 
the others; oxydizable, and soluble by 
the fixed alkalies, the oxyde being soluble 
in all the acids, and imparting to the dif- 
ferent solutions various vivid and lively 
colours. it is these salts which give the 
red colour to those of the platina. 
2. Osmium, a metal hitherto irreduci- 
ble, the oxyde of which, in the form of a 
Proceedings of Learned Societies. 475 
black powder, is extremely volatile, hav- ° 
ing a strone-odour; it is very fusible, dis- 
sélves reaculy in water, exhales with at 
the form of vapour, to which it im- 
parts a strong taste and smell. The so- 
lution becomes of a blue colour by. the 
addition of the smallest quantity, of tinc- 
ture of gails, 
“We xnow not, adds M. Cuvier, whe- 
ther to be most astonished at, the singula- 
rity of this mineral, or the sagacity and 
perseverance with which it has been re- 
duced to its original elements. 
The chrome which was several years 
ago separated from crude platina. by 
Vauquelin, has lately been discovered by 
M. Laugier to form a component part of 
meteoric ‘stones. It has.since been 
found by M.. Thenard, in those which 
lately fell near Alet, in the department 
of Gard, and which the Academy of 
Nismes caused to be collected, and sent 
to the Institute. a 
These stones, the fall of whiclris.equal- 
ly well authenticated as that of the for- 
mer, differ from them, however, consi< 
derably in colour and consistence, being 
blacker, and more friable. 
But from the 
analysis of M. Thenard, they would ap- 
pear to contain nearly the same princi- 
ples, only the metais ane more oxydized, 
and the proportion of carbon is some- 
what greater. This result, we are m+ 
formed by M. Cuvier, has been, verihed 
‘and confirmed by a committee of the 
physical class of the Insatute. 
Welast year, proceeds theveporter, in- 
timated the opinion of -M. Pacchiami, 
respecting the composition of muriatic 
acid, which, he conceived, could be pro-: 
duced by depriving water of a portion of 
its oxygen by means of the galvanic pile. 
This discovery would have proved of the 
greatest importance to chemical science ; 
but, unfortunately, subsequent researches 
have shewn that it was. not well founded, 
since, after the most accurate experi- 
ments, Messrs. Biot and Thenard did not 
succeed in producing it, when all sub- 
stances that could furnish marine salt 
were carefully kept at a distance from - 
the apparatus. > 
During the yeat1806, a work on the sub- 
ject of retraction has been published byM., 
Biot, the origisal intention of which, we 
are informed, was to aid the progress of 
astronomy. ty the course of his labours 
the author was led; however, to apply 
the action of different bodies upon hgbt 
to the analvsis or transparent substances. 
It has-been long known that the rays 
of lizht are refracted when they pass 
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