Scientific Intelligence. — Natural Hlstonj. 163 



fr ' 



have a difFereut composition from the non-magnetic grains. They 

 are separable by the magnet. 



Minerals from the OuraL 



1. JVischne Tagilsk. — TJiis ore of platuia has an obscure grey 

 color, and contains many magnetic grains, some of which possess 

 polarity, and tlie largest of them, to such an extent as to raise small 

 fragments of steel wire, 



I have analyzed the magnetic grains separately from the non-mag- 

 netic. The results of some of these analyses do not entirely agree; 

 yet the difference is so small as to prove that the two varieties pos- 

 sess a peculiar and constant composition. I shall cite but one of 



■ 



these analyses, selecting that which I deem most accurate. 



Grains non-raagnetic. Grains magnetic. 



Platina, ' - - ' - 78.94 - 73.58 



Iridium, - - - 4.97 - 2.35 



Rhodium, - - - 0.86 - 1.15 



Palladium, - . - .28 - 0.30 



Iron, - - - 11.04 - 12.98 



Copper, - - - 0.70 - 5.20 



Osmiuret of iridium in grains, 1.00 



" " in scales, .96 

 Insoluble matters. 



2.30 



98.75 97.86 



2. Goroblagodat . — This ore is entirely non-magnetic, and is re- 

 markable for containing no iridium. I ought to remark, however, 

 tliat I found a trace of it in one specimen; and there may be found 

 here and there, tliough rarely, grains containing iridium 



Platina, . . . . • 



Rhodium, . . . . • 



Palladium, . . . . ■ 



Copper, . • • ,• 



Iron, , . . • • 



Osmiuret of iridium, . • . • ^ •'*" 



86.50 



1.15 



1.10 



.45 



8.32 



"^ 



r 



98.92 



In these three analyses a part of the loss consists m osmmm, winch 

 distils during the acid solution. I have however thought best to give 

 only an approximated estimate of its quantity, as the experiments 

 vvidi respect to osmium constituted the last portion of my work. 



