Fig. 96. {upper) The wing-bolt is unscrewed, very slowly at the last, when the slightly 

 compressed air hisses out. Through the hole, the more delicate instruments are handed out. 

 Fig. 97. {lower) The most painful part of the whole dive for the divers is when they 

 emerge, tired and cramped, with feet asleep, and haul themselves out of the fourteen-inch 

 opening of the door. 



