402 Transactions. — Chemistry. 



this alloy to reduce copper from its acid solution of cupric 

 sulphate, is very singular, as hoth iron and nickel rapidly effect 

 a reduction, separately. This fact shows that the two metals 

 are (in the alloy) combined with each other, and it shows, 

 besides, the unreliability of the copper test for demonstrating 

 the absence of iron alloys from our rock masses, this test being 

 as yet the only one in use for this purpose. Possibly there is 

 a connection, and a close one, between this alloy and the 

 nickeliferous pyrrhotine of the West Coast, which I identified in 

 1878. 



Nickel some time ago was quoted at 12s. the pound ; it is 

 supplanting silver (as nickel-silver) for many purposes, such as 

 for harness. 



The mixed sand, or wash No. 2, accompanying the alloy, 

 also contained a similar substance, but in smaller grains, while, 

 besides gold — which has escaped the rough appliances of the 

 miners — it contains two kinds of platina, one markedly ferri- 

 ferous, the other nearly pure. It besides contains tin ore 

 (cassiterite) in quantity, a fact which it appears the contributors 

 did not suspect. This is a new locality for tin ore, and a great 

 deal further south than are any of our other deposits of this 

 ore. The following is the proportional composition of this 

 sand : — 



Nickeliferous alloy . . . . . . 24*77 



Tin ore 32-14 



Magnetite 19-68 



Various . . . . . . . . . . 23-41 



10000 



Art LXII. — On Platinum Crystals in the Ironsands of Orepuki 

 Qoldfield. By W. S. Hamilton. 



[Read before the Southland Institute, 26£/i January, 1886.] 



I have obtained several crystals of platinum from this source, 

 which, though minute, are tolerably perfect, one of the largest 

 of which is figured. It is a square flat tablet, 

 very perfect on three sides, but irregular on 

 the fourth, with one corner deformed. The 

 entablature is very distinct on the face pre- 

 sented, but not on the obverse. There are 

 markings on the surface, as if thin squares and 

 parallelograms of metal had been beaten into 

 it, giving it somewhat the appearance of a 

 brick floor, and suggesting a compound crystal built up of smaller 



