of Colour in Mineral Cameleon. 295 
a Valcool; 1 collected from the water a little azote, with car- 
ponie and inflammable acid ; which last indicated that an alco- 
holic matter remained with the alkali. The jar was speedily 
penetrated by the potash. I repeated the same experiment with 
potash @ Ja chaux. | did not obtain any inflammable gas ; but 
the jar was penetrated as in the preceding experiment. The 
vameleon of the first experiment was green; but when diluted 
gn water it did not yield a permanently coloured dissolution. 
The cameleon of the second experiment, being put into water, 
did not disengage any remarkable quantity of oxygen; the liquor 
which it yielded was of a permanent green ; heated by mercury 
without the contact of the air, it became discoloured without 
presenting any of the colours of the series; but when carbonic 
acid was added it presented the whole series. In order to pre- 
vent the corrosive action of the potash upon the jar, I made an- 
‘other experiment, in which I heated 30 gr. of oxide with 270 gr. 
of carbonate of potash which had been reduced in a great mea~ 
sure by the heat into subcarbonate. The jar was not in this 
instance affected, and the result J obtained was a mixture of 
about two volumes of carbonic acid and one of oxygen. The 
cameleon produced was of a greenish blue ; put into water, it 
precipitated a good deal of the oxide, of which part was mica- 
_ceous and part was dissolved, and imparted a green colour to 
the water; but this solution lost its colour so quickly, and was 
besides so slightly charged with oxide, in comparison to the 
quantity which had been heated, that 1 do not regard this ex- 
periment as absolutely conclusive of the supposition, that the 
native oxide of manganese loses oxygen on uniting itself to pot- 
ash—though it certainly renders it very probable. 
11. If the explanation which we have given of the colours of 
cameleon is exact, is it not probable that some minerals may be 
enamelled with blue, with violet, and with purple, by green and 
red combinations of manganese? Is it not probable that the 
alkaline substances, earthy or vitreous, which become tinged 
with red by the oxide of manganese, exercise upon ii; the same 
action as the acids? And may not a combination of this sort 
along with a green alkaline vombination of the same oxide, foria 
mixtures of colours analogous to blue, violet, indigo, and purple 
cameleons? In short, does there not seem some analogy as to 
chemical action between the oxide of manganese and certain ve- 
getable colouring principles, which become green by the alkalies, 
and red by the acids? 
T4 XLIX, On 
