Lightning Conductors in Shij)s. 357 



18. The manner in which conductors here proposed are applied 

 to the mast, gives the form of the whole, — that of a flattened, conical 

 surface, — wide at the base, and diminishing gradually to a point. It 

 has been stated by one of the most eminent of the French philoso- 

 phers, that this form is the best possible for a lightning-rod. 



19. 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 dis- 

 charge from 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 inferred, that much damage may be the consequence : — That in 

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

 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 principal 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 objec- 

 tions all the attention which their connection with so important a ques- 

 tion demands. 



20. The notion that a lightning-rod is a positive evil, will be found' 

 to have arisen out of the fact already mentioned (8), namel}', 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 explo- 

 sion ; and from this circumstance, they have been considered to ex- 

 ert an attractive force upon the matter of lightning, so as to draw it 

 aside from its destined course, to the destruction of the substances in 

 connection with them. 



