MEMOIR XX.] THE ALLOTROPISM OF CHLORINE. 



299 



sliding them on one another that the aperture leading 

 into A was shut, but that leading into B was open. 

 The vessel A was thus filled with dry chlorine and se- 

 curely closed. 



In the next place I filled B with dry hydrogen, which 

 was done as follows : To a bottle, Gr, Fig. 50, containing 

 dilute sulphuric acid and zinc, a dry ing- tube, 

 K, of chloride of calcium was adjusted, and at 

 its upper end a cork, A, arranged so as to re- 

 ceive tightly the tube c. In a short time, 

 therefore, B became full of dry hydrogen, the 

 surplus escaping through the open aperture^?. 

 The two ground-glass plates were now moved 

 on one another in such a manner that they 

 mutually closed one another. The vessel A 

 was therefore filled with dry chlorine, and the 

 vessel B c with an equal volume of dry hydro- 

 gen, without communicating for the present 

 with one another. 



I had provided two sets of these tubes as 

 nearly alike as they could be made, and operated with 

 them in the following manner: 



In a dark room I filled the tube A of each of them 

 with dry chlorine in the manner just described, and con- 

 fined it by sliding the plates. One of the tubes was 

 retained in the dark room and kept carefully screened 

 from the light, but the other was set for half an hour in 

 the sunbeams. The chlorine which was in it underwent 

 the specific change the object of this Memoir to de- 

 scribe. 



After restoring this tube to the dark room and wait- 

 ing a few minutes for it to gain the same temperature 

 as the other, the tubes B c of each set were filled with 

 dry hydrogen in the manner described. In each in- 

 stance, as soon as the plates were moved on each other 



Fig. 50. 



