300 On Lightning Conductors to Powder Magazines. [No. 99. 



power of a lightning rod to be equal to 250 in a unit of time ; 

 I believe that the 750 parts in excess, will in the same unit or 

 instant, pass off in every direction to surrounding objects, strik- 

 ing those which offer it the best conducting path. 



20. In proof of this assertion, I refer to the accident to Dr. 

 Goodeve's house, which I have already reported. Dr. Goodeve's 

 house is twenty feet from Mr. Trower's. Dr. Goodeve while 

 walking in his verandah saw the lightning strike Mr. Trower's 

 conductor, and at the same moment strike his own house ; 

 taking, as might be anticipated, the window bolts, and other 

 metallic bars in its course. 



21. Let me cite another and a most important fact from M. 

 Arago's rich collection. The house of Mr. Raven in Carolina 

 w r as provided with a conductor formed of an iron bar, fixed in the 

 roof — a brass wire outside the wall thence led to another metal 

 bar planted in the earth. The conductor was struck by lightning, 

 the wire was melted as far as the ground floor — the lightning 

 then pierced the masonry of the wall at a right angle, exactly 

 where a gun was standing against the wall in the kitchen ; the 

 barrel was struck, but uninjured, the stock broken, and thence 

 the electric matter passed to the ground. 



22. Here we have clearly lateral deviation from a conduc- 

 tor, and the excess passing to the nearest conducting object. 

 The wire was disproportionately small for the quantity of the dis- 

 charge ; it was fused, and the excess passed to the adjacent 

 conductor. It will be objected, that this would not have hap- 

 pened, had the lightning rod, or wire, been of the ordinary 

 dimensions, that the conductor could not have been fused, and 

 the lightning could not have left it. In reply, I point once 

 more to Dr. Goodeve's house. Mr. Trower's conductor was 

 not melted, and yet Dr. Goodeve's house was simultaneously 

 struck. 



23. Look to another fact, cited by Arago. A French vessel 

 of war, La Junon, was running before a brisk gale. A copper 

 conductor of twisted wires led from the main-mast head to 



