LOWRY. 



Phil. Mag. Ser. 6,Vol. 28, PI. X. 



(a) Copper arc. 



(b) Blank. 



(') " Combined " gas (re- 

 versed arrangement) 



(3 spark-gaps >- 



ozonizer) 



('/) " Coaibined " gas (or- 

 dinary arrangement) 

 (ozonizer ■ — ■ — >- j 

 Bpark-g ips). 



(<?) 17 Spark-gaps. 



