Advantage of elevated pointed Conductors. £59 
u Under did alone ; that is, the rounded end would caufe 
“ an explofion at a confiderable diftance, and the point 
“ little or none, notwithstanding it was brought clofe to 
“ the fubftitute.” 
I muft beg to intrude a little more on your time to 
remark on that part of Mr. Wilson’s paper, where from 
his experiments he feems to conclude, that the lightning 
at Purfleet firft ftruck on the point of the rod of the 
conductor, and then, by a lateral part of that ftroke, 
ftruck the cramp on the coping ltone. I believe, if he 
had examined the fituation of the lfone, and the place 
where the cramp was ftruck, he would have found, that 
if the lightning had ftruck on the point of the conduc- 
tor, that to have produced that effect on the ftone, it 
muft after it had ftruck on the point, and paffed down a 
quantity of metal, have ftruck from the metal up into the 
air, then down again on the cramp, and then again to 
the metal it had left, for the fraall dent or hollow made 
by the lightning was on the upper furface of the ftone, 
and yet the metallic communication to the earth conti- 
nued from the point under the ftone which was ftruck. 
It appears more probable to me, from the trifling damage 
it did, that the charged cloud had paffed over the pointed 
conductor, and had been exhaufted of a great part of 
its eledlricity in palling; and that after it had paffed, 
5 O 2 it 
