342 



THE FARMERY. 



[Chap. III. 



foUowiug view 



SECTION XXI.-LIGHTNIXG CONDUCTORS-PROTECTION OF FARM 

 BUILDINGS FROM FIRE. 



_T is a great question for the owner of farm buildings 



whether he can protect them from destruction by liglit- 



ning-rods. Being almost faithless ourselves, 3«et not quite 



sure that lightning-rods are all useless, we will give the 



opinions of several who have investigated the question. 



3G5. Opinions of (lie Valtio of Lightning f »!nluctors. — Mr. 



Quinby, a practical electrician, gave the 



of the subject in an article in the Wo)-king Farmer 



"There can be few subjects of equal importance less gen- 

 erally understood, or perhaps more universally misunder- 

 stood, than the science of electricity in its application to 

 lightning-rods. The errors of the past are very slow of erad- 

 ication, although it must be admitted that progress has been 

 made since the famous discussion in George III.'s time as to 

 whether lightning-rods should bo pointed or blunt at the top. So little is 

 known of electricity itself, and so largely is it a purely speculative science, 

 that it is no wonder that doctors disagree. 



" It is clear that the most valuable opinion on tliis subject is to be looked 

 for from those Avho have made the study of electricity and thunder-storms a 

 specialty, with the practical result in view of ascertaining the most eflPectual 

 means of protection, and it is to be remarked that those who have done this 

 have arrived at similar conclusions. 



" It is a common error to suppose that lightning-rods should be insulated, 

 and a very natural one, arising from a superficial view of the subject. It 

 should be remembered that currents of electricity in a rarefied state are con- 

 tinually circulating through masses of matter silently and without producing 

 any manifest eflccts ; the effect of insulation is to interrupt the flow of these 

 currents, whereas the lis'htninj'-rod ouo-ht rather to be so contrived as to fa- 

 cilitate their free passage from the building to the rod, and thence to the at- 

 mosphere, and vice versa. 



" During that disturbed, electrified condition of the atmosphere, which 

 we call a thunder-storm, these currents circulate in greater volume and 

 rapidity, and a sufficient interruption of them brings about a discharge of 

 lightning. 



" At such times the insulation of the rod from the building is a most ex- 

 cellent device for causing an explosion of accumulated electricity either 

 from or into the building, as the case may be. The rod, on the contrary, 

 ought to act somewhat as a safety-valve, as regards any electrical disturb- 

 ance within the house, neutralizing it gradually, and thus preventing an 

 explosion. 



