20 U. CHEISTIAN HOFFMANN ON A SPECIMEN OF 



made up of very irregular-shaped grains aud pellets, a small proportion of which had 

 perfectly smooth surfaces ; the greater number, however, were more or less pitted, but 

 none of them contained any visible inclusions of chromite. The larger portion of this 

 material was composed of grains varying in size from half to one and a half millimetres, 

 the balance measuring two millimetres, together with a few measuring three and four 

 millimetres in diameter. 



Sub-portion e. — This weighed 3'0753 grams, aud had a specific gravity of 15-332. It 

 consisted of very irregular-shaped grains and pellets, about one-third of which measured 

 two millimetres, and the remainder, which included a pellet measuring eight millimetres, 

 three millimetres in diameter. All the grains and pellets composing this material were 

 very much pitted, and contained a little imbedded chromite. 



Analyses of these sub-portions showed them to have the following composition : — 



d. e. 



Platinum 81-17 75-14 



Palladium 009 0-09 



Rhodium 1-85 1-51 



Iridium 076 1-36 



Osmium .... 



Copper 2-68 5-34 



Iron 1014 9-35 



Osmiridium 2-58 5-21 



Gangue (imbedded chromite) 0'55 2-13 



99-82 100-13 



Specific gravity 16-789 15-332 



The osmiridium found in these two sub-portions was, in both instances, present in 

 the form of minute, thin, shining, steel-grey colored scales. 



Here again, adding together the weights of the material comprising these two sub- 

 portions, also the amounts found of each of the several constituents, calculation showed 

 the magnetic portion of the ore, as a whole, to contain : — 



Platinum 78-43 



Palladium 0-09 



Bhodium 1-70 



Iridium 1-04 



Osmium 



Copper 3-89 



Iron 9-78 



Osmiridium 3-77 



Gangue (imbedded chromite) 1-27 



99-97 



Specific gravity 16095 



The composition of the non-magnetic, as compared with that of the magnetic portion, 

 was therefore as follows : — 



