On the Artificial Formation of Minerals. 295 
The occurrence of apatite in the magnetite beds of Scandi- 
navia, and the composition of the bog iron-ore of the same 
locality, suggested the possibility that the former might have 
originated from bog iron-ore under the influence of chloride 
of sodium at a high temperature. The bog iron-ore contains, 
besides, oxide of iron, phosphoric acid, lime, silica, titanic 
acid, and carbonaceous organic substance. The latter ingre- 
dient might correspond to the remarkable bituminous sub- 
stance of the magnetite beds ; and the silica, lime, and mag- 
nesia might be supposed to form, with oxide of iron, the 
numerous compounds of the amphibole series occurring in 
the magnetite beds, while apatite and titanium compounds 
might also be derived from the constituents of bog iron- 
ore. 
For the purpose of ascertaining the behaviour of bog iron- 
ore when melted with chloride of sodium, a direct experiment 
was made with a pound of the ore, and half a pound of chlo- 
ride of sodium. The cooled mass presented cavities which, 
when the chloride of sodium was dissolved out, were found 
to contain apatite crystals. The ore itself had become black, 
strongly magnetic, and had acquired such a hardness as 
scarcely to be scratched by steel, together with a perfectly 
conchoidal fracture. 
In the larger cavities the mass was covered with small, 
sharply defined crystals, which, when magnified, were found 
to be regular octahedrons. The ore was therefore actually 
converted into magnetite, and the phosphoric acid had sepa- 
rated, as apatite, from the oxide of iron. In a comparative 
experiment with bog iron-ore alone, it did not show any 
signs of fusion or crystallization; the colour, though dark- 
ened, was still brown. 
There is a great amount of evidence for the opinion that 
the blue tinge of some minerals, especially silicates and alu- 
minates, is intimately connected with the presence in them 
of phosphate of iron, and that vivianite is the hydrate of the 
compound, to which the colour of cyanite, sapphirine, spinell, 
and corundum, as well as of fluorite and apatite, is owing, at 
least in many instances. The author having ascertained, by 
analysis, the presence of phosphoric acid and iron in these 
