C 1 
qnence towards ctonftru&ing exact Charts of the King- 
dom, to afcertain this Relation by Obfervations, which 
confifted only in forming Triangles along the Parallel 
of ‘Paris, and obferving at the two Ends the Diffe- 
rence of the Meridians, by the moft exact Methods. 
The Difference, which I have now mention’d, 
feem’d to me to be fo confiderable, that I was in hopes 
of being able to determine it by Means only of two 
Places within Sight of one another, and fituatc to the 
Eaft and Weft; provided their Difference of Longi- 
tude were accurately obferved, independently of 
Aftronomical Obfervations, by means of lighted Fires; 
after the Manner that M. Pic art put in Practice in 
1 Denmark , for determining the Difference of Longi- 
tude of the Aftronomical Tower at Copenhagen and 
of Uraniburg in the Ifle of Huen. With this In- 
tent, in the Month of April 1720, I went fome 
Diftance from Paris Southward, to the Places which 
I judged moft proper for my Purpofe; but my Defign 
was not then executed, for want of Afliftance, andfor 
other Reafons, which 1 fhall pafs in Silence. 
Since that Time, I faw with Pleafure, that the Mar- 
quis Poleni had hit upon the fame Thought with me ; 
as may be feen in his Letter to the Abbot Grand i, 
dated in November 1724. 
The Dedfion of this famous Queftion of the Earth’s 
Figure had ftop’d there, when in the Year 1733, the 
Minifter of France having thought it neceflary to con- 
ftruCt an exact Map of the whole Kingdom ,• and be- 
ing inform’d, that the Work could not be better car- 
ried on than by the Aftronomers of the Royal Aca- 
demy of Sciences, applied to M. CaJJini on that Head *, 
who 
