[ 3+3 ] 
time, might be computed from the angle PTO v 
= P Q^x fine of TPD-r TQ, which, luppofing 
the nutation of the pole to be performed in a circle, 
whofe radius is 8" , or a mean between the two con- 
jugate femi-axes of the ellipfis, in which it really 
moves, is — W' x tangent of the fun’s declination 
X cofine of the difference of fun’s right afcenfion, 
and the longitude of the moon’s afcending node. 
But this is not the only miflake in the computa- 
tion of the equation of time in the Connoiffance des 
Mouvements Celeftes, though it may exceed one 
lecond of time. M. Delalande fays that the fum of 
the equation of the fun’s centre, the difference be- 
tween his longitude and right afcenfion, and the 
fum of the four little equations, muff be converted 
into mean folar time, in order to find the equation 
of time; and adds, that no exadt equation table 
could be had, before this time, for three reafons, 
one of which is, that it has always been the practice 
to convert the equation of the fun’s centre and the 
difference between his longitude and right afcenfion 
into time of the Primum Mobile, inftead of mean 
folar time, which, fays he, may produce an error 
of 2 4- feconds. 
Now I muff here freely own, that as I could not, 
without fome reludlance, and only from the fulled 
proof, allow all the mathematicians and aftronomers, 
before this time, to have been miftaken in the man- 
ner of converting the quantities above-mentioned 
into time, fo I can find no reafon to conclude fo 
from what has been cited above: on the contrary, 
from a full confideration of the fubjedt, I apprehend 
the method hitherto ufed by the mathematicians to 
be 
