Whether Lightning Rods attract Lightning. 595 



Similar effects were observed in His Majesty's ship Sapphire, 

 armed with pointed conductors of the same kind. Captain Wel- 

 lesley, who commanded this ship, states, that " the lightning was so 

 vivid, and the flashes so quick in succession all around the ship, 

 that although the duty to be done was important, I hesitated to ex- 

 pose the crew to them ;* yet the ship was not struck." In another 

 place he states, " that the Sapphire, often met with very severe 

 lightning, but it was never attracted to her."f 



The frequent instances in which lightning avoids the most pro- 

 minent parts of buildings, and falls obliquely upon some point far 

 removed from them, may be further adduced as evidence against 

 the attractive influence of such projections. The long zig-zag 

 track of lightning, arising from the resistance of the air to its more 

 direct path, may cause it to fall very obliquely on the earth's sur- 

 face, as is well known : indeed, some of the directions of the zig-zag, 

 may become almost horizontal. Now, in these cases, the pointed 

 extremities of a tower, or the masts of ships, have no influence 

 whatever on the course of the explosion ; which, on the principles 

 already explained (45), finds its way through the least resisting in- 

 terval. Mr, Alexander Small states, in a letter to Dr. Franklin, that 

 he saw an explosion of lightning pass before his window in a direction 

 nearly horizontal, and strike a clock-tower far beneath its summit. 



In the discharge of lightning, which fell on His Majesty's ship 

 Opossum in the English Channel, in March, 1825, " a peal of 

 thunder burst on the main rigging, and split the top-mast capj." 

 Her Majesty's ship Pique was struck by lightning in the St. Law- 

 rence, in November, 1839, by a discharge which fell on the fore- 

 mast just beneath the head of it, and from thence passing down 

 the mast, did considerable damage. Such cases, although compa- 

 ratively rare, and to a certain extent exceptions to the general 

 course of lightning, are still sufficient to show how little the direc- 

 tion of electrical explosions is determined by the influence of points 

 considered as mere attractors, and that it is only when they can 

 contribute to the equalization of the opposite electrical forces, that 

 lightning strikes on them. Franklin, in endeavouring to draw off 

 the electricity of a charged sphere by means of a pointed wire, 



* They were afraid to hoist the boats out. 

 f Report of Commission on Shipwreck by Lightning. J Ship's log. 



