| OCR Text |
Show 494. [M. P.] flowing Buildingrflonz Lightning. On Me Dfi of pointed Candné‘t'or: in 495 it, when a great body of cloud comes on to heavily that the pointed rod is rendered more negative: and farther, that if aflmée mzflK/all from the cloud that the above repelling operation on fragments cannot take place. more likely to be drawn to that pointed rod, than flrokes; as well as conduft‘ others that fall upon over a building, furnilhed with fuch a rod, it is to a blunt one; as being more ftrongly negative, EXPERIMENT VI. Oppofite the tide of the prime conductor place fipnratdy, ifolated by wax items, lVlr. Canton's two boxes with pith balls fufpended by fine linen threads. On each box, lay a wire lix inches long and f of an inch thick, tapering to a {harp point; but {0 laid, as that four inches of the painted end of one wire, and an equal length of the é/zznt end and ofconrfe its attraction tlronger.--And it feems more eligible, that thelightning fhould fall on the point of the conduelor (provided to convey itinto the earth,) than on any other part of the building, thence to proceed to fuch conduétor.-Which end is alfo more likely to be obtained by the length and loftinefs of the rod; as protecting more extenflvely the building under it. of the ot/Jcr, may project beyond the ends of the boxes; and both at 18 inches difiance from the prime conduélor.-Then charging the prime conduétor by a turn or two of the globe, the balls Of each pair will ftparate; thofe of the box whence the point projects moi'r, coifldernfly; the others [fix-Touch the prime conduflor, and thofe of the box with the Munt point will calla/fly and join. Thofe connected with the point will at the fame time approach each other, till within about aninch, and [bare remain *. Oéfcr'vntion. t/Je conmzmziaztimz quite down into the moif't earth, this objection might then have weight; but when fuch compleat conductors are made, the lightning is invited not into the building, but into the 8(17'1'17, the litnation it aims at; and which it always feizes every help to obtain, even from broken partial metalline conductors. ‘ V This feems a proof, that though the final] {har- pened part of the wire mutt have had a left natural quantity in it before the operation, than the thick biuut part; yet a greater quantity was driven (is-zen from it to the balls. It has been OBJECTED, that erecting pointed. rods upon cdficer, is to invite and draw the lightning into tin/n; and therefore dangerous.--~VVere fuch rods to be erected on buildings, wit/Jon! continuing Thence it is again inferred ‘ [For though the conduélor is difcharged, the air about it is not. E. that It has alfo been fuggefled, that from their electric experiments not/Mtg certain can ée concluded as to (be great operationr. oj'nnture; fince it is often feen that experiments, which have l‘ucceeded irr final], in large have failed-1t is truethat in me- chanics this has [ometimeshappened- But when it is confidered that we owe our firt't knowledge: " ' ' or. o ‘llllllllUllllllnlm |
