Lightning Conductors in Ships. 165 



philosophers, that this form is the best possible for a lightning 

 rod. 



20. The objections made to fixing lightning conductors in 

 ships, are for the most part such as have been urged against 

 lightning rods generally ; and are principally as follows : — It is 

 said, that by fixing continuous lines of metal in the masts, we 

 invite an electrical discharge fi-om the atmosphere, and that by 

 means of an attractive power, which, it is assumed, the metal is 

 possessed of, the explosion is drawn exclusively upon the vessel; 

 that, inasmuch as we can never come to know the absolute 

 quantity of electric matter which may be discharged from a 

 thunder-cloud, it is possible that the transmitting power of any 

 conductors we can apply, may be inadequate to the end in view, 

 so that they may possibly become fused ; and hence it is infer- 

 red, that much damage may be the consequence : — That in 

 fixing lightning conductors in the masts, we can only have sur- 



Jhce; whereas, the properties of a conductor depend on the 

 mass, and not on the surface of the metal : hence the metallic 

 surface is calculated to do considerable mischief, by conducting 

 the lightning into the body of the vessel. Such are the princi- 

 pal objections to this application, and which, it is hoped, are 

 fairly stated. They are highly deserving serious consideration, 

 but they will be found, on examination, to be inconsistent with 

 experience, and with the known laws of electrical action. We 

 shall, however, by a candid inquiry, give these objections all 

 the attention which their connection with so important a ques- 

 tion demands. 



21. The notion that a lightning rod is a positive evil, will 

 be found to have arisen out of the fact already mentioned (8), 

 namely, that lightning invariably passes through the line or 

 lines of least resistance between the points of action ; hence it 

 seizes on all those substances which oppose the least resistance 

 to its passage ; metallic vanes, vane spindles, iron bars, knives, 

 and pointed metallic bodies, generally, will therefore be very 

 commonly found in the course of the explosion ; and from this 

 circumstance, they have been considered to exert an attractive 

 force upon the matter of hghtning, so as to draw it aside from 

 its destined course, to the destruction of the substances in con- 

 n«ction with ihem. 



