MEMOIR XX.] THE ALLOTROPISM OF CHLORINE. 289 



inverting the bulb, and with one finger closing the ex- 

 tremity c, the gas disengaged could be trans- ^-^ 

 ferred to a graduated vessel and measured. A ( ) 

 I satisfied myself by several variations of this 

 arrangement that the small quantity of water 

 introduced from time to time when the gas 

 bubble escaped from the end of the tube c 

 exerted no essential influence on the phenom- Fi =- 45 - 

 enon. The following table shows the amount of gas 

 evolved in the dark during the periods indicated. 



The bulb having been exposed to the sunshine, in ten 

 minutes the evolution of gas commenced, and in an hour, 

 0.107 cubic inch having collected, this was thrown away 

 and the arrangement placed in the dark. To prevent 

 the undue escape of the chlorine, the flat piece of glass 

 d was laid on the open end of the tube c. In each suc- 

 cessive hour the quantity of gas given in the following 

 table was then evolved: 



First hour... ,. 0.0162 



And for four days afterwards gas was collecting in the 

 bulb in diminished quantities. 



V. This evolution of gas in the dark is not merely a 

 gradual escape of oxygen, originally formed while the 

 solution was exposed to the sun, but is traceable to an 

 influence continuously exerted by the chlorine arising in 

 properties it has acquired during its exposure to the 

 rays. 



If a bulb which has been exposed to the sun be raised 

 by a spirit-lamp to such a temperature that its gaseous 

 constituents are rapidly evolved, its extremity dipping 

 beneath some of the solution in the bottle, after allowing 



T 



