642 JAMAICA. 



A former building on the Eddyftone rock was fet on fire by light- 

 ning. The fixing a condudtor therefore on the prefent light-houfe 

 was thought highly proper; and it was refolved to put up a con- 

 du(5tor laithoiit a point, that no lightning might be unnecejfarily foli- 

 cited to the building; and that all the lightning, which accidentally 

 fhould fall on it, might be conveyed away without injuring it. This 

 condudor was fixed twelve years ago, and the building has fince re- 

 ceived no injury from lightning. 



Upon the lame principle this gentleman protefts againft elevating 

 the condudtors or rods too great a height above any building. " The 

 " longer the condudtors are above any building, the more danger may 

 "be apprehended from them; as they will then approximate nearer 

 " in their eftedts to thofe that are pointed." 



It is, I think, pretty clear from the remarks offered by Mr. Wilfon, 

 that Mr. Franklin, when he made his eledl:rical experiments, was 

 confidering only how he fliould befl: invite or draw down the matter 

 of lightning ; and that he found parp points anfwered this purpofe 

 better than others. But the great and effential principle being, 

 " that lightning, when it defcends towards the earth, prefers a me- 

 " tallic condudlor to every other, and will readily leave any other for 

 " it;" the conclufion is plain, that there can be no polTible reafon 

 given, why we fljould ufe methods to invite a ftroke; fince all that is 

 required for our fecurity is, to catch that body of lightning on a 

 metallic condudtor, and convey it fafely into the earth ; which body 

 of lightning would otherwife, and if no fuch metallic condudor had 

 been provided, have entered the fubftance of the building, and per- 

 haps laid it in ruins. I have feen feveral points taken from rods or 

 (::bndudi:ors that had been ftruck by lightning in North-America, and 

 the metal of all of them appeared to have been greatly afFedled by the 

 eledlric adtion ; the fine apex of fome was difiblved into a little round 

 ball; others had undergone a greater degree of fufion ; whilft; fome 

 were only bent into a crooked figure, but the points of all were ren- 

 dered obtufe. This variety of effedl was occafioned by the greater or 

 lefs quantity of the fluid which had fallen on them; the points, by 

 redfon of \\\t\x Jinenefs alone, were fufed or diflipated, as a very Imail 

 wire would have been in the fan^e fituation, whilfi: the thicker parts, 

 and the rods themfclvcs into which they had been riveted, remained 

 Uninjured, but condudcd the lightning fafely to the earth ; whence 

 it is certain that, if no fuch points had been fixed in the rods at all, 

 "^rhe latter would have condudted equally as well without^ as with 

 them. 



Many 



