120 



Mr. J. Burke on the Luminescence 



that were adjustable so that the ring could be moved up and 

 down, carried the wire gauze, b, which was tightly fastened 

 to it. A plate of glass, c, was laid on the mouth of the 

 receiver, and the contact made air-tight ; d were articles 

 such as glass bottles &c. ; an electromagnet, e, supported a 

 hammer,/, which fell and smashed the glass plate, c, when 

 the circuit was broken at g. The part of the cylinder above 

 the gauze was screened from the observer's sight. 



Fig. 2. 



AIR PUMP 



The air in the cylinder having been exhausted, no light 

 was seen to penetrate the gauze, neither was there any lumi- 

 nosity seen in the vicinity of d, when the external air was 

 allowed to enter the receiver, in the usual manner, by breaking 

 the glass, c. 



A bladder was then used instead of glass plates, but the 

 results were similar. 



Different gases were allowed to issue forth from bottles 

 containing these gases in a highly compressed state, on the 

 surface of glass, and especially on its sharp edges, but without 

 producing any visible effect. 



These results do not seem to harmonize with hypothesis (1). 

 Let us now proceed to the consideration of hypothesis (2). 



Fig. 3 shows the arrangement by which air could be allowed 



