and 'Longitude of the Royal Obfcrvatory at Greenwich. 1 8 j 
mine the difference of meridians of Greenwich and Paris to 
great exa&nefs. But they do not feem to me likely to throw 
any new light on the difference of latitude of the two Obfer- 
vatories, becaufe the uncertainty we are ffill under about the 
true figure and dimenfions of the earth, and the irregular attrac- 
tions arifing from the irregular external figure and unequal den- 
fity of the internal parts of the earth would prevent us from draw- 
ing any accurate conclufions, or fuch as we could confide in, from 
thofe geometrical meafures, with refpedt to fo large a quantity 
as 2° 38' 2 6 /7 the difference of latitude; and, at all events, it 
muff be lefs exaft, as it is lefs direfft, to determine the difference 
of latitude of two places from the meafured diftance of the 
two parallels compared with the length of a degree in the in- 
termediate latitude, inferred from former meafures of degrees, 
which were themfelves determined with the help of affrono- 
mical obfervations, than to infer it from the immediate affro- 
nomical obfervations made at the two obfervatories, in the 
manner I have already deduced it. 
NEVIL MASKELYNE, 
Affronomer Royal. 
Greenwich, 
February 21, ijSj. 
E 1) 2 
