Several system failures were attributed to breakdown of 

 wire and connector insulations under the high voltage 

 imposed upon them. Replacement was impracticable be- 

 cause of the expense and long lead time involved in foreign 

 purchase transactions. The construction of the bulb, which 

 demanded that each unit be individually mounted, required 

 very careful hand-wiring and insulating. 



Figure 2 shows a pair of lamps and mounts installed on the 

 bathyscaph. The only U. S. -made bulb with characteristics 

 similar to those of the Belgian type was the General Electric 

 AH-6 (fig. 3), which is a liquid-mercury bulb requiring an 

 even higher voltage. Although one AH-6 was used success- 

 fully on two dives, it was apparently only by chance that 



Figure 2. Mercury vapor lamps of original lighting 

 system shown mounted in tandem as originally used 

 on bathyscaph. 



