512 W.»H. Melville — fosephinite, a new Nickel-Iron. 



excludes this mineral. In physical and pyrognostic characters 

 and to some extent, also, in composition it agrees fairly with 

 bronzite (enstatite). The probable silicates to occur in this 

 association are pyroxene, olivine, enstatite, from which serpen- 

 tine is derived, while a feldspar is not to be expected. I did not 

 determine to which silicate the sodium-oxide belonged, owing 

 to its small quantity and the small quantity of insoluble sili- 

 cate in the pebbles. A mixture of a soda-lime feldspar and 

 enstatite (or pyroxene) would answer the requirements of the 

 ratio, but this is purely speculative. So far as the data go it is 

 best to regard this silicate as an impure bronzite. 



During attempts to purify the silicates it was noticed that 

 on the removal of the metallic part by a neutral concentrated 

 solution of either cupric sulphate or mercuric chloride that the 

 silicate was more or less attacked. Magnesia was removed, 

 and one analysis showed that out of 2*69 per cent MgO in the 

 pebbles only 043 per cent remained in the purified silicate. 

 Curiously no iron or lime was removed. Pulverized olivine 

 and serpentine were each digested with copper sulphate on the 

 water bath two or three hours ; a yellow copper salt was 

 deposited and a large quantity of magnesia was taken out of 

 both silicates.- A basic copper sulphate was produced, and the 

 liberated sulphuric acid (S0 3 ) combined with magnesia to mag- 

 nesium sulphate. In the presence of olivine or serpentine this 

 treatment for the purification of the silicate is inadmissible. 



Chromite. — Under the microscope a minute quantity of 

 black metallic grains can be seen in the siliceous portion, which 

 do not precipitate copper from a sulphate solution. These 

 grains consist of chromite with a very few strongly magnetic 

 particles of magnetite. 0*04 per cent of chromium was found 

 in the pebbles, while the per cent of chromium corresponding 

 to O'Vl per cent of chrome iron is 0'036. The presence of 

 chromite is naturally expected in the serpentine. 



Magnetite. — The few grains mentioned under chromite were 

 dissolved by protracted heating in hydrochloric acid. Other 

 particles of magnetite were not recognized with certainty. 



Two magnetic pebbles were found among those which 

 carried the large percentage of nickel, and a small amount 

 of fibrous serpentine (not chrysotile) adhered to this magnetite. 

 It is probable that magnetite occurs in the original deposit 

 from which the nickel pebbles were transported. The high 

 percentage of iron obtained by Mr. Hampton was probably 

 due to the presence of some magnetite-pebbles in the average 

 sample which he studied. 



Pyrrhotite (Troilile). — The monosulphide of iron could not 

 be separated from the other principles with sufficient purity 

 for analysis. The amount of this mineral, formula Fe 7 S 8 , was 



