RESPIRATION 



349 



the bottom. It will be seen (i) that the dive took twice as long a 

 time, and (2) that when he reached surface the maximum super- 

 saturation was 36 lbs. (2.4 atmospheres), so that he would run a 



Time in minutes. 



Figure 91. 



Diving to i68 feet by old method: Diver 14 minutes on the bottom and 84 



minutes under water. The curves from above downward represent, respectively, 



the variations in saturation of parts of the body which half saturate in 5, 10, 20, 



40, and 75 minutes; the thick line representing the air pressure. 



most dangerous risk. It is evident from the figure that the slow 

 descent and most of the slow ascent were simply adding to the 



Time in hours. 



Figure 92. 

 Theoretical ascents of a diver after a prolonged stay at 213 feet of sea 

 water. Stage decompression in 309 minutes compared with uniform decom- 

 pressions in 309 minutes and in 10 hours. Continuous lines = stage decompres- 

 sion : interrupted lines = uniform decompression. Thick lines = air pressure : 

 thin lines = saturation with atmospheric nitrogen in parts of the body which 

 half saturate in 75 minutes. 



