74 MR. WILLIAM STURGEON ON LIGHTNING 



the time it was struck. Had the lightning not entered the 

 boundaries of the rigging ahaft the main-shrouds, they, and 

 other parts of the cordage, would probably have suffered to 

 a very great extent ; and, had the ship's sails been spread, 

 the damage from such a flash of lightning might have ex- 

 tended to a great part of the rigging. 



42. With respect to the ruptures in the conductor, and 

 its being started from the mast, they were results that had 

 been foreseen, and were clearly pointed out as probable oc- 

 currences, in the Memoir on Marine Lightning Conductors, 

 previously noticed (36); in which it is stated, that "a 

 conducting strip of copper, close jammed to the wood, within 

 a groove in the mast, might probably not only be burst asun- 

 der, but })eeled from the wood for many feet upwards and 

 downwards, from the point where the lightning struck the 

 mast."* The correctness of this view of the effects of light- 

 ning on conductors fitted into grooves in the masts, has been 

 further verified on H.M. ship Sc^lla, 18 guns, which was struck 

 by lightning on the main-royal-mast, August 16, 1843, whilst 

 on the West India station. It appears that, in this case, 

 the mast was struck below the truck by an oblique flash ; 

 and that " some of the butts of the copper plates (forming 

 the conductor) in the topgallant-mast were started, and in 

 one place buckled up at the edges; some of the fixings also 

 were shook and loosened."! 



43. In addition to the remarks already made respecting 

 the inefficiency of pointed conductors (13), the three cases 

 last described (39 — 42), require particular attention; because 

 each ship had its complcmentof conductors, one in each mast, 

 in place, at the time they were respectively struck by 

 lightning ; and, as the whole of the royal-masts were stand- 

 ing, there was every chance afforded for the pointed extre- 

 mities of the conductors to ward off the explosions. The 



* See my " Scientific Researches," quarto, p. 363. 

 t Harris's " Remarkable Examples," &c. 



