aro “ESSAYS Anp OBSERVATIONS | 
and take out the merid.. parallax anfwer-) 
ing to each longitude. Half the fum of. 
thefe gives the rift part, and half their 
difference the 2d part, to be added to the 
firft when the merid. par. for the given 
long. © is greater than the other, and to. 
be fubtracted when lefs. In like manner, 
the equation for the femid. © confifts of 
two parts; the 1ft of which is propor- 
tional to the fine, the 2d to the cofine of 
lat. The rf{t part is the equation for the 
given long. @, and 6 hours from noon; 
and this fabtra@ted from the equation for, 
the given long. © and hour from noon, 
gives the 2d part. 
15 THE famerules will ferve for find- 
ing the moon’s parallaxes from a fixed ftar 
or planet. If the femid. of the planet have 
no fenfible magnitude, there will be no 
place for the correction mentioned in 
art.6. But, as the requifites could not be 
found from the common tables, if the 
{tar has latitude, it will be convenient, 
firft, to fuppofe it has none, and after=- 
wards to apply a proper correction. . Be- 
fides, the proceeding in this way will make 
. the 
