Nonvay 



297 



whole joint, the effect being to twist the soft copper tubes into 

 reversed spirals, within which the line wires are so tightly grasped 

 that the parts in contact are permanently protected from the 



DOUBLE COPPER TUBE BEFORE TWISTING 



COPPER TUBE AFTER TWISTING 



FIG. 99 



weather. This joint is shown in fig. 99. When it is considered 

 desirable to solder, the form of joint shown in fig. 100 is used : 

 the heat being applied at the point A, can have no effect on the 



FIG. 100 



running wire.^ When too much vibration is set up in the houses 

 it is damped by placing several inches of wire on each side of the 

 insulator (fig. 101) in a split vulcanised rubber tube, and then 



LEADEN WIRE 



INDIA-RUBBER TUBE 



FIG. ioi 



tightly twisting over all two spiral layers of heavy leaden wire or 

 strip. The central station fixture is a large and substantial structure 

 built up of channel and angle iron, but devoid of decorative preten- 



