WORK UNDER PRESSURE AND IN GREAT HEAT 391 



A number of experiments in the steel chamber at pressures 

 up to 6| atmospheres were carried out on men, with stage decom- 

 pression ; and many dives in the sea to pressures of from 4 to 



75 



J3 

 o 



s 



3 

 c 



01 





a 

 3 

 o 



30 



y ~/ ^^ \ ' \ J \ 



5 10 15 20 25 30 35 40 45 50 S5 60 65 70 75 60 



Time in minutes. 

 Fig. 2. — Diving to 28 fathoms by old method. The thick line represents the air-pressure. 

 The curves, from above downwards, represent respectively the variations in saturation 

 of parts which half saturate in 5, IO, 20, 40, and 75 minutes. 



7^ atmospheres have also been made by Lieutenant Damant 

 and others, with the time-limits and stage decompression recom- 

 mended in the new diving tables. No symptom of caisson 

 disease has, however, been observed, so that the new method 



A 

 a 



a 



3 



4) 



3 

 3 

 o 

 a 



30 



25 



45 



Time in minutes. 

 Fig. 3. — Diving to 28 fathoms by new method. The curves, from above downward, represent 

 respectively the variations in saturation of parts of the body which half saturate in 5, io r 

 20, 40, and 75 minutes. The thick line represents the air-pressure. Diver 14 minutes 

 on the bottom and 46 minutes under water. 



appears to be practically successful. The old method was to 

 go down and come up slowly at a rate of about 5 ft., or 

 1 1 metres per minute. The accompanying diagrams show the 



