Chap. 6.] tfbtjafeft Situation in a thunder Storm. 353 



municated to the public, in a treatife on this fubject *, 

 fome effentials to be obferved in the erection of con- 

 ductors to buildings : he advifes, that the uyper fif- 

 teen or twenty inches of the -rod fhould be compofed 

 of copper> and not of iron, as the latter, being expofed 

 to the weather, will ruft, and ruft does not conduct 

 electricity j that the iron part of the rod fhould Jbe 

 painted, but not the upper part of it, becaufe paint is 

 no conductor He further advifes, that the upper ex- 

 tremity of a conducting rod Ihould not only be accu- 

 rately pointed and finely tapered, but that it .fhould 

 be extremely prominent, about ten or fifteen feet above 

 all the parts of the building which are the neareft it. 

 It may be added, that a conductor Ihould always be 

 carried in the earth fome feet beyond the foundation 

 of the building, and Ihould, if poffible, terminate in 

 waten 



The fafeft fituation during a thunder ftorm is the 

 Cellar j for when a perfon is below the furface of the 

 earth, the lightning muft ftrike it before it can reach 

 him, and will of courfe, in all probability, be expend- 

 ed on it. Dr. Franklin advifes perfons apprehenfive 

 of lightning to fit in the middle of a. room, not un- 

 der a metal luftre, or any other conductor, and to lay 

 their feet up upon another chair. It will be ftill fafer, 

 he adds, to lay two or three beds or mattrefles, in the 

 middle of the room, and folding them double> to place 

 the chairs upon them. A hammock fufpended by 

 filk cords would be an improvement upon this appa- 

 ratus. Perfons in fields fhould prefer the open parts 

 to the vicinity of trees, &c. The diftance of a thun- 

 der ftorm, and confequently the danger, is not difficult 

 to be eflimated. As light travels at the rate of 



* Principles of Eleftricity, p. 205. 



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