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BELL SYSTEM TECHNICAL JOURNAL 



sion in distilled water, gradually absorb more water than was contained 

 in the original latex, though the sheet still retains its original form, 

 somewhat swollen of course by water absorption. On the other hand, 

 rubber which has been carefully freed of all water-soluble impurities 

 absorbs but a small percentage of water under the same conditions. 

 Fresh-water cables are more liable to degradation from water absorp- 

 tion than cables in salt water, and if the ocean were a saturated solution 

 of sodium chloride the problem of the use of ordinary rubber would be 

 materially simplified. 



A development of primary importance in this connection has been 

 the elimination of the proteins from rubber. It appears that the pro- 

 tein constituents form an intricate network which permeates the entire 



Fig. 2 — High grade gutta-percha in shapes popular with the forest gatherers. 



mass. While the amount of proteins present is too small to cause a 

 large absorption of water, they do insure that such water as is absorbed 

 causes a maximum electrical damage by extending the water-bearing 

 filaments through and through the material. The partial hydrolysis of 

 the proteins and the thorough coagulation of any remaining residues by 



