[ 49 ] 
IX. Obfervations upon Lightning , and the 
■ Method of fecuring Buildings from its Ef- 
fects : In a Letter to Sir Charles Frede- 
rick, Surveyor-General of His Majefly s 
Ordnance , and F. R, S. By Benjamin 
Wilfon, F. R. S. &> Ac . R . Upf. Soc. 
S I R, 
Y OUR Ration, as Surveyor- General of His 
Majefty’s Ordnance, being fuch, as makes 
the fubjedt of this paper particulary interefting to 
you, I prefume an apology for this addrefs will be 
wholly unneceffary. 
Upon an application of the Board of Ordnance to 
the Royal Society, in July laft, a committee was ap- 
pointed, to confider of the properell method for fe- 
curing the Magazine at Purjleet from mifchief by 
lightning : which committee reported to the council 
of that learned body, what they thought neceflary 
to be done upon that occafion. The council, after- 
wards, tranfmitted to the board, a copy of that re- 
port, together with another paper written by myfelf, 
in confequence thereof. 
Vol. LXIII. H For, 
