[ 633 ] 
venient direction fo difpofed as always to touch the 
Pea water. By thefe means the accumulation of the 
matter of thunder and lightning, will be prevented 
to a confiderable diftance from the (hip, by its being 
dilcharged filently by the wire, which will not be done 
by the mads; as thefe from their height, figure, and 
conflituent parts, without an apparatus of this kind, 
tend to diredt and conduct the lightning into the fhip. 
But for a further explanation upon this head, I beg 
of your Lcrdfhip to cad your eye upon volume 48. 
page 215 of the Philofophical tranfa&ions, where I 
have confidered this matter more at large. 
The applying wire to the mads of fhips will be nei- 
ther difficult nor expenfive; as a brafs wire of the 
thicknefs of a large goole quill, I am of opinion, 
will in moil cafes be large enough to anfwer this 
purpofe. I prefer brafs wire to iron, as the former 
is lefs liable to rufl than the latter ; and any metal 
corroded by rufl to the center, ceafes to be of any 
ufe, in diredting the lightning in the degree hoped 
for and expedled by this apparatus. The entering 
into a minute detail of the rationale of this procefs 
would take up too much of yourLorddiip’s time; from 
analogy only I will mention to your Lordffiip, that 
the fame quantity of gunpowder, which confined in 
a clofe place, will throw down a tower, or rend a 
rock, will, when fired loofe in the open air, be al- 
moft inorfenfive. 
Thunder dorms are very frequent and fevere in Pen- 
filvania, and great mifchiefs often happen from them ; 
but I am informed by Dr. Franklin, that fince an ap- 
paratus of the kind above mentioned, placed at the tops 
of the houfes has been generally uled at Philadelphia, 
4 M 2 not 
