TEE WORLD'S ADVANCE 



ing themselves after a diver or sand-hog 

 has been at work, and it is this lag that 

 was not properly considered until a short 

 while ago. This tardy action on the 

 part of the tiny blood vessels is the real 

 reason for peril to the pressure worker. 

 When the sandhog or the diver is de- 

 compressed too rapidly, especially in the 

 final stages, nitrogen remains in the out- 

 of-the-way regions of the body and has a 

 pressure then in excess of that of the 

 far more active arterial and venous sys- 

 tems, and is also greater than that of 

 the external atmosphere. You have seen 

 bubbles liberated in charged water when 

 the cork was removed. In a general way 

 that is what would happen in the inner- 

 most parts of a pressure worker's body 

 if his return to normal or the period of 

 his decompression were not a progressive 

 and a suitably prolonged performance. 



immediate flood of the active blood cir- 

 culation. 



But don't conclude from this that a 

 man can breathe air at high pressure 

 without running a risk. The worker 

 must have an increased percentage of 

 oxygen, and oxygen consumes the tis- 

 sues, and if exposed to this attack too 

 long a man would be poisoned by the 

 very excess of this life-giving element 

 under pressure. Therefore, a limit is thus 

 imposed upon man's venturing into the 

 ocean's depths, even though slow decom- 

 pression when rising toward the surface 

 would save him from the baneful effects 

 of the nitrogen contained in his body. 



Once developed, these bubbles may press 

 against a nerve center and produce 

 paralysis or they may get into the cir- 

 culation, reach the heart, and induce 

 death. Strange to say, the investigators 

 found out it was not so much the great 

 air pressure within the diving suit that 

 caused the trouble, but rather the after- 

 effects if the surcharged nitrogen were 

 not properly drained from the capil- 

 laries and the tissues lying beyond the 



The Experimental Chamber 

 in which Drs. Leonard, Hill 

 and Greenwood Underwent 

 Air Pressures Slightly in 

 Excess of that in a Diving 

 Suit at a Depth of 210 Feet. 

 In the Oval: A Steam - 

 Driven Air Compressor 

 Charging the Reserve Tank 

 from which the Diver is 

 Supplied with Air. 



Now another thing that has to be taken 

 into consideration in diving operations 

 in the ordinary elastic suit is the accu- 

 mulation of carbonic acid gas this poi- 

 sonous element increasing directly with the 

 amount of physical effort made by the 

 deep-water worker. This gas is heavy 

 and can be cleared from the metal helmet 

 only provided the circulation of air be 

 abundant and the pressure of it a trifle 

 in excess of that of the water outside into 



