334 Prof. Draper on the Allotropism of Chlorine, 



same theoretical constitution as chlorine-water. Berzelius and 

 Balard suppose, that in this solution chlorous or hypochlorous 

 acids exist. It might be inquired, if this be the condition of 

 things, why does not an exposure to heat alone evolve oxygen ? 

 for chlorous acid is exceedingly liable to decomposition by 

 slight elevation of temperature; and we should be justified in 

 inferring, that if any of this acid is to be found in chlorine- 

 water, it would be decomposed at the boiling-point. M. Millon 

 adopts the view, that the bleaching compounds are metallic 

 chlorides, analogous to the corresponding peroxides. But 

 the ninth fact seems incompatible with this view. If chlorine 

 water is analogous to peroxide of hydrogen, and the last be 

 what its name imports, and not merely oxygenated water, it is 

 difficult to understand why, when chlorine water is boiled, 

 oxygen is not given off. If the atom of chlorine and the atom 

 of oxygen in this body are placed under the saqie relations to 

 the atom of hydrogen, it seems necessary that the chlorine 

 atom at 212° Fahr. should expel the oxygen atom and chlo- 

 rohydric acid form. It is probable, indeed, that the two oxy- 

 gen atoms in peroxide of hydrogen are related to their hydro- 

 gen atom with different degrees of affinity, and that one of 

 them is retained far more loosely than the other. But this 

 would correspond with our ideas of oxygenized water and not 

 peroxide of hydrogen, and leads us to the conclusion that the 

 solution employed in this memoir is strictly a solution of chlo- 

 rine in water. 



XI. The decomposition of chlorine-water when placed in 

 the sunbeam does not begin at once, but a certain space of 

 time intervenes, during which the chlorine is undergoing its 

 specific change. 



I need quote no further instance of the truth of this than the 

 experiment given in support of the second ftict. This is the 

 same phaenomenon which takes place when chlorine and hy- 

 drogen are exposed together; they do not begin to unite at 

 once, but a certain space of time elapses, during which tlie 

 preliminary tithonization is taking place, and when that is 

 over union begins (Phil. Mag., July 184'4'). 



On the Relations of Chlorine and Hydrogen, 



We have thus traced the cause of the decomposition of 

 water, in the case before us, to a change impressed upon the 

 chlorine by exposure to the rays of the sun. In this decom- 

 position three elementary bodies are involved, chlorine, oxy- 

 gen and hydrogen. 



We can therefore reduce the problem under discussion to 



