OF METALS OF THE PLATINUM GROUP. 
645 
K. 
The above figures show the proportion of gold found by analysis at the different 
points of the hemisphere Iv. The result is a complex one, a rich alloy of gold and 
aluminium falls to the bottom of the mass by gravity, about 8 per cent, remaining in 
solution, and, on freezing, the gold becomes concentrated externally from the mother 
liquor. 
The alloy L, of gold 90 per cent, and aluminium 10 per cent., was then made by 
first melting the gold and subsequently adding the 10 per cent, of aluminium, w'ell 
stirring, and casting into a similar spherical mould as with the other alloy (K). 
This alloy was very fluid, its fracture hard, white, crystalline, and very brittle. 
The whole of the interior, when the sphere was cut in two halves from top to bottom, 
showed purple-pink spots throughout; but from the bottom of the hemisphere to the 
centre a pyramidal cone of white crystalline metal showed itself distinctly through 
the mass, in the direction shown by the dotted line. Its specific gravity was 11 '96. 
About kilogs. were employed for this experiment. 
Alloy L. Gold. 900 parts. 
Aluminium. 100 ,, 
Parts in 1000 of gold :— 
Outside. 
Intermediate. 
Centre. 
888-3 
866’6 
882-3 
899-5 
892-3 
883-3 
903-8 
864-7 
864-8 
879-5 
Average . 880 
Maximum difference in the gold between centre and mean of outside, 2‘3 per thousand, 
