352 Account of « Meteoric Stone 
ash into it, which produced but a slight change of colour, which 
I ascribe to some traces of manganese rather than to nickel; 
and yet there was so small a quantity that it would not have 
been perceptible in the scales. 
The sulphuric acid, therefore, in acting on this aérolite, had 
only dissolved the magnesia, the silex, and the iron. 
Examination of the Residue, which was insoluble in the 
Sulphuric Acid. 
It was interesting to examine the nature of the portion of the 
meteoric stone which refused to be dissolved in the sulphuric 
acid: it must necessarily have been of a nature different from 
that which had been dissolved. 
This residue when examined with the glass seemed to be com- 
posed of two different substances; one in white and brilliant 
particles; the other black, and giving to the mixture of both a 
slate-gray colour. 
The acids not having any action on this residue, I treated it 
with twice its weight of potash at ared heat. The matter when 
fused and cold had a greenish-yellow colour ; when diluted in 
water it communicated to it a beautiful yellow colour, which 
left no doubt as to the presence of chrome. After having washed . 
this matter until it no longer gave colour to the water I satu- 
rated the liquor with the nitric acid, and evaporated to dryness. 
On treating this residue again with water, the nitrate of potash 
and chromic acid were dissolved, and there remained silex, which 
I set aside, in order to add it to that which we had previously 
obtained and to that of which we are going to speak. 
The nitrate of mercury put into the above yellow liquor, in 
fact produced a precipitate of a fine orange red. 
The portion of the residue treated by ‘potash, and which was 
not dissolved in the water, was treated with the nitric acid, which 
dissolved the greatest quantity of it: that which it left was of a 
very deep gray colour: the nitric solution evaporated to dryness 
with care, and the residue taken up with water sharpened by ni-. 
tric acid, left a white powder which was still silex. 
The miktie ‘solution examined with care, did not exhibit any 
iron, and not an atom of nickel. 
The portion of the residue which had resisted the acid and 
the alkali, and which had a deep gray colour, appeared to be 
pure metallic chrome, and perhaps with an alloy of iron: never- 
theless it was not affected by the magnet. What is certain is, 
that when melted with borax it communicated a fine green co- 
lour to it, similar to that of common chrome. 
It results from the above experiments, that the meteoric stone 
‘ which 
