Mr. milner on the 
510 
quired to be done in the cafe of the Sun’s unequal adlion 
on the protuberant parts of the equator. The exceffes 
or defeats of that unequal action are to be considered as 
forces applied to thole parts, which would move them 
according to the different circumftances through un- 
equal fpaces proportional to the forces in equal times of 
action, provided the particles were at liberty to move 
freely in the directions in which they are urged; and, 
laftly, the real fpace mult be computed through which a 
particle moves at fome known diftance from the center 
of the earth in confequence of thefe various forces. This 
whole procefs will not differ from the eafy example al- 
ready defcribed, except in the length of the calculation, 
and the proper management of the doCtrine of fluxions; 
and it feems advifable in difficult fubjedts always to begin 
with fimple inftances before we proceed to thofe which are 
more complex, and to diftinguifh the algebraical opera- 
tions from the principles upon which they are founded. 
§ 4. In order to determine how much any particle of 
the earth is affeCted by the unequal aCtion of the Sun 
(fig. 2.), let cadb reprefent the earth, s the Sun at a 
great diftance, and cd a plane perpendicular to the line 
st joining the centers of the Sun and earth. If sk or st 
reprefent the accelerating force of the Sun on a particle at 
the earth’s center, and sl be taken to sk in the duplicate 
ratio 
