[ >53 3 
XIX. On the Computation of the Sun s' 
Difance from the Earthy by the Theory 
of Gravity : In a Letter to Mathew 
Maty, M. D, Sec. R. S, from the Rev. 
Mr. Horfley, F. R, S. 
$ I R, 
Read June i, 
1769 
A LITTLE Treatife, that has lately 
been publiflied, againft Dr. Stew- 
art’s method of determining the diftance of the Sun 
by the theory of gravity, has put me upon re- 
x^onfidering a fubjedt which I had long ddmilTed 
from my thoughts. I am far from being convinced 
lliat Dr. Stewarts conclufions are erroneous upon 
his own principles,” as his antagonift affirms; and 
l am well fatisfied that there is no error in the prin- 
ciples themfelves. I have always been fenlible that 
an extieme precifion was recjuifite in determining 
the mean quantity of the folar force affedfing the 
moon s gravity towards the earth, in order to obtain 
an accurate eftimation of the diftance; and this cir- 
cumftance was mentioned by me, in a paper that I 
communicated to the Society about two years ago'^, 
before it had been remarked, that I knew of, by any 
other writer upon the fubjedt. I muft now declare, 
that the imperfedtion of the method ariling from this 
SeePhilof. Tranf. vol. LVII. for 1767, p. 179, 183, 
VoL. LIX. X 
circum 
