EXPERIMENT STATION BULLETINS. 



203 



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 & . MetJiocf of S(/J>jborf//^^ fbo/n f. 

 ,5 Afefhoc/ of connecf/n^ cah/es if ci sf>ice iS necesaafi^. 



GROUNDS. 



One of the most essential parts of a lightning rod system is the 

 securing of a good connection between the conductor or cable and either 

 damp earth or water in the earth. The common term used is ''ground- 

 ing" the conductor. The ideal condition is reached when the "ground" 

 extends far enough beneath the surface of the earth to reach a permanent 

 water level. This condition is often attained in low localities or where 

 a stratum of clay is reached not far below the surface. 



The lower end of the conductor or cable should extend at least to 



