and on the Defence of Shipping from Lightning. 173 



Memoir on Marine Lightning Conductors, to which I have 

 alluded in former papers *. 



Had the question been one of private, rather than of public 

 interest, I should certainly have followed the course pursued 

 by others, who have been honoured with Mr. Sturgeon's cen- 

 sure, and have shown by my silence how little I care to de- 

 prive him of any advantage which he may consider he de- 

 rives by his coarse treatment of me. Such, however, is not 

 the case : my method of defending shipping from lightning 

 by permanent conductors of electricity fixed in their masts, 

 being still carrying out in several of H.M. ships, I feel my- 

 self called on to affdrd a clear elucidation of certain circum- 

 stances intimately associated with this highly important ques- 

 tion, which have been lately much misrepresented ; moreovei', 

 the subject is one of increasing interest, and intimately con- 

 nected with an important department of physical science. 



In the year 1780, the French began to turn their attention 

 to the more effectual defence of their buildings and shipping 

 from the effects of lightning. 



Mons. Le Roi was sent to visit Brest and the various sea- 

 ports of France for that purpose. His memoir in the Histoire 

 de Vylcademie des Sciences for the year 1790, will be read 

 with advantage by every one interested in the subject. 



Impressed with the necessity of adopting some more per- 

 manent security than was derived from the use of chains, 

 temporarily applied in the rigging, he endeavoured to place, 

 lie says, such conductors in ships as might be deemed 

 " fixed and durable." With this view long linked rods of 

 small dimensions were led from a point at the mast-head 

 along a part of the rigging, and fixed to plates of metal at 

 the ship's side communicating with the sea. These, however, 

 he admits did not stand the working of the rigging, and were 

 broken in a storm ; so that he was induced to change them for 

 similar linked rods of small size led in divided stages along 

 the masts. 



This form of conductor was fixed in the French ships of 

 war Etoile, Resolution, Experiment, Boussole, Astrolabe, 

 and in some ships destined for America. Although Mons. 

 Le Roi had reason to believe that it was sufficiently secure 

 from the effects of mechanical violence, yet it was eventually 

 abandoned in the French service, probably from its still be- 

 ing found inconvenient and ill calculated to meet the violent 

 forces incidental to a ship's mast and rigging. The only kind 



• L. & E. Phil. Mag., December 1839, February 1840, May 1840. 



