456 THE POPULAR SCIENCE MONTHLY. 



spent so much time and trouble. It was elaborately protected ; 

 protected by innumerable conductors with admirable earths made 

 in a variety of ways, bristling with points all over the top every- 

 thing carried out in the most approved style, regardless of ex- 

 pense. Yet in the month of June the building was struck and 

 set on fire. ... If a lightning conductor can prevent a flash from 

 occurring by its repellent action, well and good ; but he had 



MULTIPLE FLASH. 



shown in his lectures that there are cases where a point has no 

 protective action whatever, when a point could be struck by a 

 thick and heavy flash. There were other cases where the point 

 acts with a brush or fizz and neutralizes the electric charge with- 

 out a flash. They could not always do it. And so the lightning- 

 rod has two functions ; one is to be repellent if it can, and the 

 other is to carry off a flash when it can not help receiving it. 



