J 00 Mr. Grove on the Decomposition of Water by Heat, 



that of metallic oxides at a higher, and so on to oxide of hy- 

 drogen, there appears to be an extensive series of facts which 

 afford strong hope of a generalized antagonism between ther- 

 mic repulsion and chemical affinity, and a consequent esta- 

 blishment of the law of continuity in reference to physical and 

 chemical attraction. 



The deposit from chlorine, to which I have alluded in my 

 paper, I have since examined, and though it differs in colour 

 from that described in books, I find it is a protochloride of 

 platinum, formed at the expense of the platinum wire. The 

 larger portion of the chlorine in the tube combines with the 

 hydrogen of the aqueous vapour, and the muriatic acid is 

 absorbed by the water; when the experiment terminates the 

 gaseous volume is reduced to nearly one-half, and this residue 

 is oxygen. 



This effect induced me to try an ignited wire on other ana- 

 logues of chlorine, and I tried bromine and chloride of iodine 

 in the apparatus (fig. 5). The tube was filled with the liquid, 

 and its extremity was in the first experiments immersed in 

 another narrow tube of the same liquid as that which filled it. 

 When the platinum wire was ignited, permanent gas was 

 given off both from the bromine and from the chloride of 

 iodine, which gas on examination proved, to my surprise, to 

 be oxygen. In one experiment I collected half a cubic inch 

 of gas from an equal volume of chloride of iodine. As the 

 experiment in this form required too large a quantity of the 

 liquid to enable me to observe any change which might take 

 place in its character, I repeated it with a tube five feet long, 

 bent in two angular curves. A small quantity of the liquid 

 was placed in the extremity of the tube containing the wire, 

 which was so arranged as to be the lowest point; the angles 

 were placed in cold water and the experiment proceeded with ; 

 my object was to enable the dense vapour of the liquids to 

 shelter them from the atmosphere, there being no satisfactory 

 method of shutting them in and yet allowing room for the 

 elimination of the liberated gas, or of absorbing the latter by 

 combination without also absorbing the vapours. 



1 had hoped by the above means to proceed with the ex- 

 periments until all the oxygen was liberated that could be 

 driven off, and then to have examined the residua ; but I found 

 that after experimenting for a short time, both the platinum 

 wire and the glass in proximity to it were attacked by the 

 liquids ; this difficulty, similar to those which have hitherto 

 prevented the isolation of fluorine, I have not yet been able 

 to conquer, though I hope to resume the experiments. 



As chloride of iodine is decomposed by water, it cannot 



