294 On the Cause of the Changes 
duced by the subcarbonate of ammonia and the carbonate of 
potash ;—but is it equally so to the changes produced by distilled 
water? Ido not think it is, although indeed the purest water 
which I have been able to obtain has always presented some 
sensible quantity of carbonic acid, or of subcarbonate of ammo- 
nia, Thus much I can affirm, that the intermediary cameleous 
produced by water are invariably formed of green cameleon and 
a red liquor; for all of them become green after being filtered, and 
when potash is added are converted into green cameleons. What 
proves, besides, that the carbonic acid has no influence on the 
colour of the red liquor of these cameleons is, that water which 
has been reduced by boiling to a fifth of its volume, and which 
ought to contain less carbonic acid than cold water which has 
not been boiled, being mixed when hot with green cameleon, red- 
dens it much more “rapidly than cold water: and again, that 
when a little more hydrate of barytes is added to boiling water 
than is necessary to precipitate all the carbonic acid contained 
in the water, if it is afterwards turned into green cameleon, it 
will change to red, although the carhanic acid has been wholly 
extracted. Is it not possible that this red colour may be the 
result of an action of the potash upon the oxide less strong than 
that exercised by the same alkali upon the oxide of green came- 
Jeon? And is it not also possible, when carbonic acid is present, 
that it may have the effect of weakening the action of the pot- 
ash? 
10. The oxide of green cameleon possesses without doubt the 
same degree of oxidation as the oxide of red cameleon, and that 
oxide contains more oxygen than that of salts of manganese un- 
coloured; so that on heating hydrochloric acid with green or 
red cameleon, the former disengages itself from the chlorine, and 
the latter becomes discoloured. Scheele has before remarked, 
that a great number of matters susceptible of absorbing oxygen 
produce the same effect of discoloration as hydrochloric Abid 
But it may be asked, Does the cameleon contain the natural oxide, 
or the oxide which is produced by exposing the latter to the ac~ 
tion of fire? If we consider the ‘impossibility of uniting the first 
to acids without subjecting it to a previous deoxidation; that ca- 
meleon supersaturated with sulphuric, nitric, and other acids 
forms red salts, in the same manner as the second of the oxides 
referred to; and further, that carbonic acid reddens green came- 
leon without producing any effervescence,—it would seem to fol- 
low that the oxide of cameleon is less oxidated than the natural 
oxide. I have made several experiments to ascertain the cor- 
rectness Of this conclusion. I heated in a stone jar 25 grammes 
of the oxide of native manganese with 200 grammes of potash 
a Valcool; 
