Fig 3,3 Bottom view of FNRS-2 showing pressure sptiere and float (Jacques Placard) 



The pressure sphere was larger than the 

 BATHYSPHERE (6-ft 7-in. diam.) and was of 

 two cast-steel (Ni-Cr-Mo) hemispheres bolted 

 together at an equatorial flange. Entry 

 through the hatch was made while FNRS-2 

 was on deck; once the passengers were in- 

 side, there was no way for them to get out 

 unless the bathyscaph was lifted clear of the 

 water. 



Of the many innovations produced by Pic- 

 card, the viewports of FNRS-2 stand out as 

 truly significant. Having witnessed the 

 BATHYSPHERE'S problem with cracking 

 and chipped glass, Piccard, as early as 1939, 

 teamed with countryman Professor Guiltisen 

 and produced a conically-shaped window of 

 acrylic plastic 5.91 inches thick, 15.75-inch 

 outside diameter and 3.94-inch inside diame- 

 ter. The conical shape offered wide-angle 

 viewing (Fig. 3.4) and plastic, unlike glass, 

 does not fail catastrophically; instead, it de- 

 forms elastically and passes on excess stress 

 to its adjacent parts. This configuration and 

 plastic are the bases of all submersible view- 



Fig 3 4 Professor Auguste Piccard inspecting an acrylic plastic viewport, one ot his 

 many contributions to deep submergence (Jacques Piccard) 



37 



