VOL. LXm.] PHILOSOPHICAL TRANSACTIONS. 379 



dentally fell on it, might be conveyed away without injuring it. This conductor 

 was fixed 12 years ago, and the building has since received no injury from 

 lightning.* 



There is another edifice of great consequence, I mean St. Paul's church, 

 which stands much exposed, from its height, to accidents by lightning. The 

 dean and chapter of that cathedral thought it an object deserving the serious at- 

 tention of the Royal Society. A committee was therefore appointed, in conse- 

 quence of their application: and proper conductors were put up, in the several 

 places where they were thought necessary, from the top of the lantern to the 

 sewers underground. And notwithstanding particular care was taken, to have 

 the additional metal either of a considerable diameter, or an equal quantity of it 

 formed into other shapes, for the conveniency of the several places; yet part of 

 those conductors, consisting of iron, in the stone gallery, showed marks of their 

 having been made considerably hot, if not absolutely red, by a stroke of light- 

 ning which happened in March last (as appears by a letter which I communicated 

 to the R. s. from one of the vergers of that church, Mr. Richard Gould) who 

 had examined the conductors the morning following, along with Mr. Burton of 

 the same cathedral,-|- and that the appearances were in general as the verger's 



* A former building erected for the sarae purpose, upon this rock, was set on fire by light- 

 ning.— Orig. 



f Mr. Gould acquaints us in his letter, that he examined the four conductors in the lantern and 

 stone gallery of St. Paul's church, the morning after the lightning happened. That no marks whatever 

 appeared on the conductor to the south, which was the first he attended to. Tliat he next examined 

 the conductor to the west, and observed a thick rust lying on the pavement in the stone gallery, as if 

 it had been cleaned off, from the conductor, with a tool : that several parts of the iron appeared black, 

 particularly the screws or nuts : something like the effects left by gunpowder on iron or steel, or a 

 smoky fire. That the conductors to the north showed no marks, no more than that to the south. But 

 that on examining the conductor to the east, he found stronger marks abundantly, than on the west 

 conductor, it being much blacker; particularly on tlie nut and screws : the rust lying in great quan- 

 tities on the pavement. And the extreme part of the conductor, that goes into the water trunk, 

 seemed like a piece of iron newly taken out of a forge by a smith, without working it on the anvil. 



Mr. Gould has since added to the account in his letter, some circumstances which I apprehend 

 ought not to be omitted. He says, that where the end of the conductor, on the east side, points to- 

 wards the water tnink, a stone surrounds part of it, leaving an interval, half an inch wide or more, 

 between them, and about 4 or 5 inches long, which is a little more than the breadth of the conduc- 

 tor. That this interval was filled up witli dirt, and had been so for some time, occasioned by fre- 

 quent showers of rain washing tlie pavement in the stone gallery. That, afl;erthe lightning happened, 

 he observed a hole was made through the dirt, one quarter of an inch in diameter, and about 2 inches 

 in length. That the hole was close to the iron; and that, on stooping down his head, he perceived a 

 very disagreeable smell of sulphur from the stone, dirt, and conductor, particularly the last. 



On hearing tliis account, Mr. Delaval and myself, a few days ago, went and examined the con- 

 ductors again ; but more carefully than before. For, on causing the stone to be removed, which 

 covered the top of the water trunk, we had an opportunity of examining near 2 feet more of the iron 

 which points to the water trunk, than we could perceive before this stone was removed. When we 



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