Catalytic Phcmomena with Allotropy. 251 



aud the noble metals and their oxides act in an exactly similar 

 manner. But it is also well known that the catalysis of peroxide 

 of hydrogen, by whatever means it be effected, always takes place 

 with an evolution of heat, from which it appears that this phse- 

 nomenon is most closely connected with the conversionof intoO. 



I hold it to be not only possible, but even highly probable, 

 that in the transformation of the various conditions of oxygen 

 into each other, the relations of this body to heat become changed . 

 Or to speak more precisely, that the specific or latent heat of 

 is different from, and indeed greater than, that of ; from which 

 it would follow, that in the transformation of into heat 

 would be set free. If we had ozonized oxygen in a pure con- 

 dition, it would be easy to prove the accuracy of this assumption 

 in the most direct manner. Such an oxygen ought, in its de- 

 ozonization by means of carbon, peroxide of iron, black oxide of 

 manganese, &c., to exhibit an elevation of temperature in case 

 my opinion were well founded. The fact, however, that a con- 

 siderable evolution of heat, which amounts in many cases to a 

 red heat, takes place in the separation of oxygen from compounds 

 in which we may assume the presence of 0, appears to me to 

 allow the supposition that the immediate cause of this phseno- 

 menon is to be sought in the transformation of combined O 

 into O. 



In this respect the comportment of chlorate of potash affords 

 an extremely instructive example. Just at its point of fusion 

 this salt disengages not a trace of oxygen ; but if only small 

 quantities of peroxide of iron, &c. be added to the melted chlo- 

 rate, not merely does a most violent evolution of common oxygen 

 take place, but such a strong disengagement of heat occurs that 

 the decomposing saline mass becomes heated to redness. 



That active oxygen is contained in the chlorate of potash is 

 clearly evident from its powerful oxidizing effects ; and because 

 the oxygen separated from the salt is O, it must have arisen 

 from 0. We can therefore scarcely seek for the proximate 

 cause of the disengagement of heat which takes place in the 

 decomposition of ^ the salt in anything else than in the trans- 

 formation of its O into 0. 



If the said d( composition consisted merely in a simple sepa- 

 ration of the oxygen contained in the salt, then, according to the 

 usual physical views not only ought no evolution of heat to take 

 place, but a decrease of temperature ought to result, since the 

 originally fixed oxygen assumes the gaseous condition. But 

 since in reality precisely the contrary occurs, this fact ajjpears to 

 me to indicate in ^the most decisive manner, that in the trans- 

 formation of the O of the chlorate of potash into 0, the relations 

 of oxygen to heat undergo an essential modification. 



