48 M. Thcnard on the [Jan. 



ment of all the oxygen without the formation of any carbonic 

 acid. 



Charcoal in fine powder and peroxide containing only nine 

 times its volume of oxygen. Brisk effervescence without heat; 

 all the oxygen is disengaged without the production of carbonic 

 acid. Pass a certain quantity of the liquor up an inverted tube 

 containing mercury, then introduce some well powdered char- 

 coal. It will be found that the gas which is readily evolved from 

 the liquor is merely oxygen, and that it will be deoxidized in a 

 very short time. 



Lamp Black. No action, unquestionably because the liquor 

 does not moisten it. 



Action upon Metallic Sulphurets at Common Temperatures. 



The greater number of the metallic sulphurets which I have 

 tried have a very marked action upon the peroxide of hydrogen. 

 Very often this action is violent, and accompanied with much 

 heat when the Hquor is concentrated. Moreover, whether it be 

 diluted with water or concentrated, there almost always results 

 a sulphate, and a more or less sensible disengagement of oxygen. 

 This occurs with the sulphurets of copper, antimony, lead, and 

 iron : they are scarcely brought into contact before they are 

 converted with effervescence into sulphates. 



The sulphurets of arsenic and of molybeden act with more 

 violence than the preceding upon the concentrated peroxide ; 

 heat and light are produced ; but no sulphate is formed ; the 

 arsenic is acidified, and the sulphur remains almost unacted 

 upon. The sulphurets of bismuth and of tin act very feebly, 

 even upon the peroxide in the most concentrated state ; the 

 sulphurets of silver and of mercury (cinnabar) have no action 

 at all. 



Action of Metallic Oxides at Common Tenqyeratures. 



In general, metallic oxides tend to restore the peroxide of 

 hydrogen to the state of protoxide or water. Some of tlieni 

 produce this effect by becoming more oxidized ; others without 

 alteration, but disengaging all the oxygen in the gaseous form, 

 which water absorbs to become peroxide. Some again disen- 

 gage the oxygen, and are themselves reduced ; but few exert no 

 action at all. 



The decomposing power of the oxides varies much. Several 

 expel the oxygen so suddenly from the liquor, that a kind of 

 explosion occurs, and then much light and heat are evolved. 

 The action of others, on the contrary, is slow, occasioning but 

 slight effervescence, and no sensible heat. 



Of the Oxides which absorb the Oxi/gen of the Peroxide, and 

 . restore it to the State of Protoxide or Water, 



These oxides are barytes, strontian, hme, oxide of zinc, oxide 



6 



