C 2 5° ] 
or the building : for it is apprehended the great 
cnurch of St. Pauls, to compleat the partial conduc- 
tors (which are the metallic crofs, ball, gallery, dome, 
&c.) and fecure it effectually, would require a bar of 
metal two inches diameter, if not more : and a build- 
ing like the Bntifli Mufeum, one confiderably lefs. 
But it appears there is no occafion for any at that re- 
pofitory, as it is already provided, though from ac- 
cident , like many other buildings, with very effectual 
conductors. The copeings of the roof thereof, and 
tile feveral fpouts, which are continued from thence 
into the ground, being all of lead. 
That conductors ought to be thicker than is gene- 
rally imagined, feems to appear from a late inftance 
taken notice of in St. Bride’s church by Mr. Delaval 
and Dr. Watfon, where an iron bar two inches and 
a half broad, and half an inch thick, or more, was 
bent and broke afunder by the violence of the light- 
ening. 
The Eddyftone Lighthoufe, which flands upon a 
rock furrounded by the fea, the work of Mr. Smea- 
ton,. was thought to be an objeCt very likely to fuffer 
by lightening ; and the more io, as the top of it con- 
fided of a copper ball two feet in diameter, with a 
chimney of the fame metal, palling through it down 
to the fecond floor, but no further. Directions were 
therefore given to make a communication of metal 
horn the lowed part of the copper chimney down to 
tne lea j which was executed accordingly about the 
year 1760, or foon after the building was finiilied. 
Now if, inflead of the copper ball, a pointed bar of 
metal had been put in its place, or above it, and 
communicated with the conducting matter below, 
there is no faying what might be the confequence of 
fo 
