rs 
Chemistry and Physics. 419 
the oxygen, contained, for instance, in the oxyd of silver previously to 
that compound being decomposed by heat, exists but in one state, be that 
State what it may, how then does it happen, we may ask, that at the 
42] 
Same time two different sorts of oxygen, O and O, are disengaged from 
the compound named? The answer to this question seems to me to be, 
that one of the two kinds of oxygen eliminated must be engendered at 
the expense of the other; or to speak more correctly, that during the 
act of elimination of oxygen from the oxyd of silver, part of that oxy- 
g¢n suffers a change of condition. Now as the oxyds of gold, silver, 
&e., enjoy the power of coloring blue the guaiacum solution, just as 
free O does, I draw from the fact the conclusion, that the condition of 
the oxygen contained in the oxyds of gold, silver, &c. is t e ozonic 
one ; and further infer, that by far the greatest portion of that O, under 
the influence of heat, is transformed into O. Why the whole of the 
