METALLIC MATERIALS IN THE TELEPHONE SYSTEM 145 



lead-calcium sheathed cable were installed on poles alongside of similar 

 lengths of cable with standard lead-antimony sheath. Various sheath 

 thicknesses ranging from .075 to the standard .125 inch were installed 

 for comparison and to expedite early failure. In addition to the 

 comparison between alloys this test will also give information regarding 

 the minimum thickness of sheath which may be employed with both 

 the standard and the experimental alloys. 



Fig. 5 — X-ray diffraction apparatus showing cameras mounted for identification of 

 structure and precision measurement of lattice constant. 



Besides their application as cable sheathing materials, lead alloys 

 are also extensively used by the Bell System as solders, storage battery 

 plates, fuses and as corrosion protection coatings. 



Copper and Copper Alloys 



Unalloyed copper finds application as wire in the lead-sheathed 

 cables already discussed, in open wire circuits and in central office 

 equipment. In the telephone plant there are eighty million miles of 

 it — enough to span the distance from the earth to the moon three 

 hundred thirty-five times. To obtain the lowest transmission losses, 

 cable conductors consist of high conductivity annealed copper wire. 



