146 Intelligence and Miscellaneous Articles. 



luted nitric acid j it possesses this property in common with urea ; 

 the acid may be separated from the precipitate by washing with 

 water. — Hensmans Repertoire, January 1829. 



ANALYSIS OF PLATINA ORES. — BY BERZELIUS. 

 Platina ore from Nischne Tagilsk in the Uralian mountains. — This 

 ore is of a dark gray colour, and contains many magnetic grains, 

 some of which possess poles, and the larger are capable of raising 

 small pieces of steel wire. The magnetic and non-magnetic grains 

 were separately analysed, and the results showed that they areessen- 



tiallj' and constantly different. Non Magnetic. Magnetic. 



Platina 78-94 73-58 



Iridium 4-97 2-35 



Rhodium 86 M5 



Palladium 0-28 030 



Iron 1104 1298 



Copper 0-70 5-20 



Osmiuret of iridium in grains 1*00 



in scales 0-96 



Insoluble matter 2-30 



98-75 97-86 



The insoluble matter of the magnetic grains was a mixture of 

 osmiuret of iridium in grains and scales, with some sand. 



Platina ore from Goroblagodat in the Uralian mountains. — This 

 ore is remarkable on account of its being entirely non-magnetic, and 

 because it contains no iridium, except that a trace of it was found 

 in one specimen, 



Platina 86*50 



Rhodium 1*15 



Palladium MO 



Copper 0-45 



Iron 8-32 



Osmiuret of iridium 140 



98-92 

 In these three analyses a part of the loss consisted of osmium, 

 which distils during the solution in the acid. 



Platina ore from Barbacoas in the province of Antioquia in Co- 

 lombia. — This ore consists of grains which frequently weigh nearly a 

 gramme (154 grains), mixed with a smaller quantity of smaller 

 grains. The larger grains consisted of 



Platina 84-30 



Rhodium 3-46 



Iridium 1*46 



Palladium 1-06 



Osmium 1-03 



Copper 0-74 



Iron 5-31 



Quartz 0-60 



Lime 0-12 



~98-08 

 AnnaJes de Chim. el de P/n/s, April 1829. 



