PROFESSOE H. B. DIXON AND MR. E. C. EDGAR 



APPENDIX. 



1. The Action of Chlorine on Glass. 



The following experiments were made to determine the action, if any, of pure, 

 dry chlorine on soft glass. Two glass bulbs of approximately equal volume and 

 weight were made. To one of these, A, was fused the inner portion of a ground 

 glass joint ; it was then cleaned and dried. The two bulbs were then suspended from 

 different pans of the balance and small weights added to one pan to bring them to 

 equilibrium. A was then fitted to the apparatus for generating chlorine, and the 

 whole was evacuated and filled with pure dry chlorine. The bulb was separated 

 from the rest of the apparatus by fusion beyond the ground-glass joint and was then 

 kept for one week. At the end of that time the ground-glass joint was taken to 

 pieces, and the chlorine sucked out and replaced by dried air. It was then weighed, 

 the other bulb acting as a counterpoise. 



Weight to counterpoise the bulb (before exposure to chlorine) . . 1 -32468 grammes. 

 (after ) . . 1 32464 



The experiment was repeated with two similar bulbs, but the chlorine was left in 

 contact with the glass for a fortnight. 



Weight to counterpoise the bulb (before exposure to chlorine) . . 2-67931 grammes. 



(after ) . . 2-67925 



Two more bulbs were subjected to similar treatment, the time of contact, in this 

 case, being a month. 



Weight to counterpoise the bulb (before exposure to chlorine) . . 1 12884 grammes. 



(after ) . . 1-12879 



These weighings show that on allowing chlorine to remain in contact with soft 

 glass for a considerable period of time, the latter loses weight very slightly. 



The bulb used in Experiment 1 was again filled with chlorine, which was allowed 

 to remain in contact with the glass for a week. 



Weight of bulb before exposure 1 32464 grammes. 



after 1-32465 



An exposure for a further period of two weeks gave : 



Weight of bulb before exposure 1 32465 grammes. 



after 1-32463 



If any action of chlorine on the soft glass bulb may be assumed to have taken 

 place, it must have occurred during the first week, as further exposure to chlorine 

 gave a constant result. 



