[ 36a ] 
firmed by a comparifon of fix differences of right 
afcenfion of flars obferved at St. Helena, with the 
fame obferved, at my defire, fince my return, at the 
Royal Obfervatory, by the tranfit inftrument, which 
gives 27' .L, agreeing exactly with what has been here 
found in a more certain manner. 
Sometimes, in making thefe obfervations, it fo 
happened, that feveral fiars lay near the moon’s par- 
allel of declination ; when I obferved all of them, 
that came within the field of the telefcope ; as well 
to obviate the hazard of miffing to obferve the right 
ftar again after an interval of feveral hours, as to ob- 
tain a greater number of comparifons of the moon’s 
motions in right afcenfion, and fo reduce the un- 
avoidable errors of the obfervations as much as 
poffible. 
It may be proper to remark, that the mod con- 
venient time for making thefe obfervations, is when 
the moon is flationary at her greateft declinations ; 
when ffie may be compared with the fame ftar, with 
a telefcope having a moderate field of view, for 
feveral hours. The change of the moon’s parallax 
in declination is then alone to be feared ; but if the 
obfervations are made nearly at the fame diftance from 
the meridian, both on the weftern and eaftern fide, 
the parallax returning to the fame quantity, will oc- 
cafion no difficulty. Sometimes, when the moon 
is not exactly at, but only near, her greateft declina- 
tion, by obferving her on the proper fide of the me- 
ridian, the effeCt of parallax may be found to be con- 
trary to, and confequently counteract, her change of 
declination arifing from her proper motion. 
Through 
