12 Construction, &c, of Lightning Conductors. 



take immediately to earth by one of the methods pointed 

 out ; and if in a tower, this will best be done by connecting 

 it with the underground water-mains ; but not to any 

 portion of the pipes above ground or in the building. 



The ridge metal should be connected by bridge strips, and 

 another conductor at the end of the roof farthest from the 

 spire should be erected and taken straight to earth, soldering 

 to the ridge in passing. An arrangement of this kind will 

 form an effective lightning conductor to such a building. If 

 there be other towers or turrets more than 60 ft. or 70 ft. 

 from the chief spire, each should have a small conductor. 



In a building without a lofty tower or spire, and where 

 chimney-stacks or gables form the highest points, the con- 

 ductors should always be placed on the highest and most 

 prominent parts, bearing in mind the proportion between 

 height and area covered by the building, and it will thus often 

 be found that even three, four, or more conductors will be 

 necessary. Let them be fixed to the stacks by holdfasts ; 

 soldered to ridges and gutters in passing ; taken over the 

 roof outside the walls, each conductor direct to earth. All 

 the conductors must be connected into one system on the 

 roof, by soldering some of the lines of ridging by bridges ; 

 and the more of the roof metal brought into the system the 

 better. 



Iron rod, of from three-eighths to half an inch diameter, 

 or tube three-quarters diameter, three-quarter inch copper 

 tube, or strips of stout sheet copper two or three inches 

 broad, or galvanized iron rope from half an inch diameter 

 upwards will perhaps be found the most useful materials ; 

 but in case of iron tube, screwing without soldering will be 

 insufficient. Copper or iron rope, from its flexibility, will be 

 found very useful ; but every joint must be covered with a 

 good mass of solder. In reference to the use of wire rope, 

 it is to be borne in mind that several strands of metal 

 arranged in the form of a rope are liable to more rapid 

 oxidation and decay than equivalent more compact forms of 

 rod or tube ; whatever forms be adopted this element of 

 decay should always be taken account of, examining the 

 continuity of the conductor from time to time. When 

 from any cause a breach of metallic continuity comes about, 

 the building becomes less secure than it would be if such 

 disordered lightning conductors were absent. The use of 

 down-pipes to save the expense of bringing a special con- 

 ductor to earth cannot be strongly recommended unless they 



