Compressed Air Work And Diving 1909

6 COMRRESSED AIR WORK should be added together, and the proper stoppages for such an exposure used during the second ascent. With an interval of one hour between the exposures these precautions may be halved, or with two hours interval may be altogether omitted, if the duration of exposure during the first dive has not exceeded that shown in the table. Table II.—This table is for use when a diver has been detainecl at the bottom beyond the ordinary limit of time by reason of some Occidental circumstance, such as getting his life line or air pipe entangled. These two tables for diving have been so arrangecl, by a slight modification in the spacing of the stoppages demanded by theoretical considerations, as to prevent any danger of “bends” in the water. It should be noted that “ bends,” which are caused by the more slowly desaturating tissues, although painful, are not so clanger- ous as other symptoms, such as paralysis. hor this reason, if the diver is in a collapsecl condition after a long exposure in colcl water, the last stop at 10 ft. might be omitted, since the stoppage at 20 ft. will already have got rid of most of the harmful excess of gas. If de- compression symptoms are feared, and no medical lock is available, the diver should be kept on the laclder for about ten minutes, so that he can be lowerecl into the water if necessary. And when he has been brought on board he might sit for another twenty minutes before undressing, still wearing his boots, helmet, &c., and merely having his front and back lead weights removecl, so that he can be sent below again at once on the appear- ance of symptoms. It will not usually be necessary for him to go to a greater clepth than that for the first stoppage, and generally a clepth of 20 ft. will be sufficient.