1 8 Mr. Bevan Lean and Mr. H. B. Dixon on 



Fig. 2. 



The means for connecting either brass junctions up to A 

 or B is shown in fig. (2). 



UV is a circular ring which when screwed up over WY 

 makes an airtight connection between the brass piece 

 and the lead tube A. 



G and H (fig. 1) are small brass tubes, provided with taps 

 by means of which A may be placed in communica- 

 tion with B, without making use of X. 



T and S are large taps in the brass junctions, connecting 

 X with A or B. The passage in each tap is 11 mm. 

 in diameter. 



Method of Experiment. After passing a current of air 

 through the apparatus, air was enclosed in the tube X by- 

 turning off the taps T and S. The tube G was then con- 

 nected with H by means of an indiarubber tube, and the 

 explosive gas passed in at L, and through the apparatus, 

 until a sample taken at F was found to explode violently. 

 The taps at E, F, G, and H were then all turned off, and 

 the platinum wires in the firing piece connected up with a 

 Ruhmkorff coil. One observer then stationed himself 

 opposite the tube X, and immediately before giving the 



