CH\P. 



LIGHTNING-CONE UCTORS. 



537 



shows any luminous brushes, but on account of the form and the great 

 conductivity of copper it resists fusion much better, without being 

 any the less effective a protection to the building. The essential thing 



FIG. 342. Conical point of red copper 

 in the lightning-conductor. 



FIG. 343. Vertical rod of the lightning-conductor. 



is that the electrical current in passing from the cloud to the lightning- 

 conductor, when the lightning falls should find an uninterrupted path 

 from the point to the subterranean stratum. 



