propojed trigonometrical Operation. jpc; 
arcs, as determined by the zenith didances of dars, taken 
with a feCtor of flx feet radius, and where the observations are 
fo nearly confident among themlekes, as to leave little doubt 
of their accuracy ; but in the 290th page of M. Cassini’s 
book, fo often quoted, as well as in the 170th page of his 
Dcfcription Geographique de fa France , publifhed in 1783, the 
latitude of Perpignan is given 42° 41' 55", which is 7" S" 7 
lefs than that deduced from the obfervations, without any rea- 
fon that I can perceive being afiigned for the reduction. 
Perpignan, the fouthernmoft dation of the meridian line 
extending from Dunkirk through the whole kingdom of 
France, is fituated at no great didance from the bottom of the 
Pyrenean mountains, where that lofty range ends at the Medi- 
terranean fea. M. de la Caille was of opinion, that the 
plummet of the feCtor mud have been affeCted by the a tt rad ion 
which it would differ from that caufe ; a fuppofition which, 
neverthelefs, has been doubted, fince the obfervations made in 
this country on the attraction of Schehallion : for by thefe it 
appeared, that the efFeCt, although fenfible, was but fmall, 
even when the feCtor was placed as near as poffible to the oppo- 
dte fides of the mountain. It is indeed true,, that the Canigou , 
the highed of the Pyrenean range, being fituated obliquely to 
the meridian, and at a confiderable didance from Perpignan, 
would not probably occafion much deviation in the plummet ; 
yet, on the other hand, when we compare the very trifling 
quantity of matter in Schehallion with the immenfity of the 
mafs in the Pyrenees, in the direction of the meridian, I can- 
not help being of M. de la CAiLLE r s opinion, that the plum- 
met of the feCtor would be fenfibly affeCted, that is to fay, it 
would be drawn to the fouthward out of its perpendicular 
direction, and would thereby give the zenith didance of the 
pole, 
