44< Dr. Schcenbein on some Chemical Effects 



fact which proves that in a voltaic point of view there exists 

 a great analogy between the simple halogenous bodies, ozone 

 and metallic peroxides on one side, and spongy platinum on 

 the other. 



After having stated a number of facts which demonstrate 

 the highly oxidizing powers of platinum, we ask in what 

 manner does that metal exalt the chemical activity of oxygen ? 

 This question has occupied many philosophers, and been 

 answered in very different ways. Faraday and Dcebereiner 

 ascribe to platinum the power of condensing oxygen so much 

 as to deprive that element of its gaseous condition, and think 

 that condensed state to be the true cause of the oxidizing 

 powers of platinum. Others (De la Rive and Gmelin) presume 

 that oxygen is capable of chemically uniting with that metal, 

 and with those philosophers it is the oxide of platinum that 

 occasions the oxidation of hydrogen, &c. Berzelius holds 

 the opinion that the oxidations caused by platinum are cata- 

 lytical phasnomena, i. e. effects produced by some unknown 

 force being innate to that metal and exalting the chemical 

 attractive powers of oxygen. 



It is not my intention to enter into a discussion of those 

 opinions; I shall confine myself to a few general remarks 

 upon that interesting subject. As the common oxides of pla- 

 tinum are not acted upon (at the common temperature) by 

 free hydrogen, as platinum foil or wire, that causes at a mode- 

 rate temperature the combustion of detonating gas, exhibits 

 a perfect metallic surface, while the thinnest film of an oxide 

 diminishes or destroys the lustre of any metal, and as pla- 

 tinum is a body that has a very weak affinity for oxygen, 

 I think that that metal is not capable of combining directly 

 with the oxygen of the air, and that De la Rive's view of the 

 subject is erroneous. But how is it with Faraday's and Dce- 

 bereiner's theory of the matter in question? It seems indeed 

 to be the true one. Satisfactory however as that hypothesis 

 may appear, it is nevertheless possible that the oxidizing ac- 

 tion of platinum may depend upon a cause different from what 

 the philosophers mentioned consider as such, 



We know that phosphorus being put in contact with moist 

 atmospheric air gives rise to the formation of a highly oxi- 

 dizing agent, which, as it has been shown elsewhere, seems 

 to be a peculiar compound of water and oxygen, and enjoys 

 the power of oxidizing a great number of substances at the 

 common temperature. Now if phosphorus enjoys that pro- 

 perty, it seems possible that some other substances, for in- 

 stance platinum and iridium, may do the same. In other 

 terms, it appears possible that platinum has the power to en- 



