92 THE BIRTH OF THE BATHYSPHERE 



chanical margins of safety, while my hopes of seeing a 

 new world of life left no opportunity for worry about 

 possible defects. 



In its final design the sphere was, compared with some 

 of the marvelously complicated "diving machines" men- 

 tioned in Chapter 2, quite a simple affair. It was not as 

 tall as a man, measuring only four feet nine inches in 

 diameter, but its walls were everywhere an inch and a 

 quarter thick and it weighed five thousand four hundred 

 pounds. A first casting had weighed twice as much, but 

 it would have been too heavy for any of the winches avail- 

 able in Bermuda and was junked. 



There were to be three windows — cylinders of fused 

 quartz eight inches in diameter and three inches thick 

 fitting into steel projections resembling the mouths of very 

 short cannon. Quartz was used for two excellent reasons 

 — it is the strongest transparent substance known and it 

 transmits all wave-lengths of light. In all, five windows 

 were ground. Mr. Barton has written that the first was 

 chipped in an attempt to grind it into its seat. The second 

 gave way under an internal pressure test of one thousand 

 two hundred and fifty pounds to the square inch. It seems 

 probable that the frame in front was bent out, and that 

 the resulting shearing strains broke the glass. The third 

 was broken when the frame bolts were tightened unevenly. 

 The remaining two, however, passed every test success- 

 fully and subsequently, during the actual dives, never 

 leaked a drop. Through one of these it was planned to send 



