[ 21 ! ] 
in which I cannot perfectly agree with him, I think 
fcarce any body is better acquainted with the fubjedt 
of electricity than himfelf. 
XXXII. A Letter to the Rev. Dr. Hales, 
F.R.S. from Captain Henry Ellis, F.R.S . 
dated Jan. 7, 1750-51, at Cape Monte 
Africa, Ship Earl of Hallifax. 
S I R, 
Read Jane 13TMAKE ufe of this opportunity of 
I75K JL writing to you, lefs from the vanity I 
have of having fuch a correfpondent, than the defire 
of contributing to his fatisfaction, who efteems it his 
greateft happinefs to promote the intereft of mankind. 
At yours and Lord Hallifax’s recommendation, I had 
your ventilators fixed on board of my fhip, at Briftol. 
The following is a detail of the experiments, which I 
made to prove their utility. 
1. I took a wax-candle, of eight to the pound, 
and drew it thro’ a mold, to make it of one thicknefs 
from end to end : then weighed it exactly, and 
lighted it in the fhip’s hold 5 where I found it wafted 
67 grains in 30 minutes j that place not being venti- 
lated during 24 hours : but after fix hours ventilation 
it wafted 94+^ grains in the fame time. 
2. I carried with me into the hold a plate of filver, 
well polifhed, and a lantern and candle, all blinded, 
except a round hole of about two inches diameter. I 
placed the plate at fix feet di fiance from it 3 and with 
D d 2 fuch 
