1122 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1957 



Fig. 14 — Cross-section of Poly (Vinyl Chloride) rod showing sulfiding due to j 

 sulfate-redvicing marine bacteria. Bottom end was in sediment — top in water. I 

 E.\posed at Daytona Beach for two years. Original magnification 1.6X. • 



general observations and broad comparisons. The locations and depths i 

 from which the samples were obtained are given in Table XIV. In most 

 cases, a sample 3-feet long is obtained. Twenty-two different pieces of 

 such size represent a rather small sample with respect to the total 

 marine environment. Here again the program assumes more value as 

 additional samples are obtained. 



The procedure employed in examining one of these cable sections is 

 about as follows. First, the over-all external condition is observed and 

 recorded. Then, the outer jute covering, armor wires, inner jute bedding, 

 and cloth and metallic tapes, if any, are removed progressively. The 

 armor wires are examined in detail by electrochemists to determine the 

 extent and kind of corrosion. The jute is tested in various ways. If 

 sufficient material is available tensile strength is measured. Microscopic 

 examination of representative fibers is also made. In the case of the inner 

 jute which is not treated with tarry materials, damage counts are run 

 according to the procedure of MacMillan and Basu.^^ According to this 

 method, deoiled and dewaxed fibers are permitted to swell in 10 per cent 

 sodium hydroxide solution. Following this they are treated in a bath of 

 133 per cent weight to volume, aqueous zinc chloride solution over steam. 

 Undamaged fibers swell as tight helices while damaged fibers swell as 

 bundles of parallel fibrils. The fibers are mounted in zinc chloride solu- 

 tion on a microscope slide and counted to determine the per cent of 

 damaged fibers. 



To examine the integrity of the insulation on the conductor, the elec- 

 trolytic procedure of Blake, Kitchin and Pratt^^ is used. An electrolytic 



