Catalytic Phanomena with Atlotropy. 253 



Now as heat changes free O, as well ^ as O combined with 

 water, into 0, it can also transform the of the several oxides 

 of chlorine into 0, and, according to my opinion, it can thereby 

 effect the splitting up of these jcompounds^into chlorine and 

 common oxygen. The O of CIO, ClO^ ClO^ undergoes, it is 

 known, this change of condition so easily, that it is dangerous 

 to handle these substances; for they decompose with detonation 

 at temperatures which scarcely reach 100°, 



We know of CIO, that in contact with charcoal powder it 

 immediately decomposes into CI and O. The same powder, 

 according to my experiments, instantaneously transforms free 

 into 0, and is known to change HO + O rapidly ^into^HO and O. 

 Now it is probable that charcoal decomposes CIO, ClO^, CIO*, in 

 the same manner that it catalyses peroxide of hydrogen, namely, 

 by changing the of these compounds. 



That chlorate of potash itself may become catalysed, not only 

 by heat, but also by a number of ponderable agents, and that 

 these substances are the same as those which effect the ^ catalysis 

 of peroxide of hydrogen, or the transformation of free into 0, 

 are also now well-known facts, and have been already mentioned. 

 Chlorate of potash, not decomposable at its point of fusion, be- 

 comes so by the presence of peroxide of manganese, peroxide of 

 iron, &c. And niy most recent experiments have proved that 

 distinct quantities of chlorine are disengaged from an intimate 

 mixture of this salt with peroxide of manganese, at a tempera- 

 ture which is far below the fusing-point of the chlorate ; which 

 proves, that under the influence of peroxide of manganese, solid 

 chloric acid, even combined with potash, may be catalysed. 



It must appear remarkable, that among the different oxides of 

 chlorine precisely that one possesses the smallest oxidizing pro- 

 perty, or shows the greatest constancy, which contains the most 

 oxygen, namely perchloric acid. It has hitherto been usually con- 

 sidered, that when oxygen combines with a body in various rela- 

 tions, tlie first equivalent of oxygen is more intimately united to 

 the radical than the second, this than the third, and so on. But if, 

 as the measure for the magnitude of the affinity existing, for in- 

 stance, between chlorine and oxygen, we take the temperatures 

 at which the various oxides of the first body^ dccomjiose into 

 thejr constituents, this affinity is smaller in C10,C10^, Cl0'*,and 

 CIO'', than in (.'10'', because the last can still exist at a tempera- 

 ture at which the other oxygen compounds of chlorine are de- 

 composed. 



In my opinion, this easier or more difficult dccomposabilityof 

 the various degrees of oxidation of chlorine does not depend 

 upon a weaker or stronger attraction between this body and the 

 oxygen, that is, upon a looser or closer union of the oxygen, but 



