Chemical Science, 185 



Platina Ore from Goroblagodat in the Oural. — This ore is not 

 magnetic, and is remarkable for containing no iridium. The pro- 

 portions were — 



Platina . . . 86.50 



Rhodium . « . 1.15 



Palladium . . . 1.10 



Copper .... 0.45 

 Iron .... 8.32 



Osmiuret of iridium . . 1.40 



98.92 

 The loss in these three analyses is partly due to osmium, which 

 distilled over during the solution of the ore in acid. 



Platina Ore from Darbacoas in the Province of Antioquia, Co- 

 lumbia. — -This ore consisted of grains often of considerable weight, 

 mixed with smaller ones. The composition of the largest was as 

 follows : — 



Platina 



24. On the Specific Gravity of Alloys and their Point of Fusion, by 

 M. A. T. Kupfer. — The author commences with detailing the me- 

 thods he employs to weigh his alloys ; in these there is nothing 

 new, and we shall confine ourselves to his final results. 



Alloys of Lead and Tin. — The metals were combined in the 

 simple or multiple proportion of the weights of their atoms, because 

 the author thought there must exist a simple relation between the 

 dilatation of these alloys and their chemical composition. The 

 weights of the atoms were taken from the table of M. Berzelius, 

 and the following are the mean results he has obtained : — 



Proportion in atoms. Observed density. Calculated density. Differences. 



