t ] 
Circle may be very good, notwithftanding the want 
of this, fuppofed neceflary. Operation. And indeed, 
that they were fo, fufficiently appears from this Faft. 
The Difference of Latitude between Tome a and 
Mount KittiSy found in September, was obferved 
again in March following, by the Help of the fame 
Star ’Draconis, and did not differ from the former 
above 3 -f- Seconds, though the Inftrument had been 
twice carried from one Place to the other. This is a 
Degree of Exaflnefs not eafy to be met with 5 no not 
in Monfieur CaJJinH Obfervations, made on different 
Stars, which differ fometimes 40 Seconds, in deter- 
mining the Amplitude of an Arc in the Heavens, 
though their Inftrument was carefully examined in 
the way above-mentioned. 
The Author then proceeds, in his Turn, to inquire 
into the Accuracy and Certainty of the two Sets of 
Obfervations made in the North and South Parts of 
France, in refpeft of the Royal Obfervatory at Taris. 
As to the Meafures of the Degrees in the Northern 
Parts of France, between Farts and Dunkirk, he 
owns they cannot be much out of the way ; being in 
fome meafure confirmed by Monfieur 7 )^ la Hire, in 
the Year 1683. and Monfieur Cajjint himfelf. Yet 
Mr. Celpus obferves, that the Bafis on the fandy plain 
Shore, near Dunkirk, when meafured again, differed 
Three Feet from the former Meafurement ; which is 
a much greater Difference than that Mr. Celjius and 
the other Gentlemen found, in meafuring a much 
longer Line twice over, which was but Four Inches. 
As to the Aftronomical Obfervations taken by the 
Six Foot Seflor, whofe Limb of 12 Degrees was di- 
vided only at every 20 Seconds? it is true, Monfieur 
CaJJim 
