C 271 ) 
As to DifFerences of Longitudes ; 
S0urd0f$ 1 C Amiens 1 fo^, 5^ 54'* 
Clernmtf \Sourdon ( \o. 1« 9. 
MareuUymott'Edi^LeMy ihm J Clermont >by<^o. o. 34. 
- Mareuil i jMalvoyJini Jo. o. 20. 
Mareuil) (^Faris j ^o. 4. 37. 
So much of the elevemh Article. The twelfth is framed upon 
zxiOhjeCtion^ that might be made, vix,, Whecher the Meafure is 
the fame taken at Parity with that which is taken upon a L.evel by 
the Sea-fide, Here he computes upon the fall of the River Seine ^ 
and judgeth the place where he meafured to be raifed above the 
Sea not more then 80 Toifes; and concludes the Difference be- 
tween meafuring at Paris and by the Sea not above S feet fer de- 
gree. Where he makes a Table of Levels-^ defcribes an Inftru- 
ment to take Levels with ; difcourfes of Refraftions, and how to 
correftthem. 
In the thirteenth Article he examins feveral opinions, dif- 
ferent from his, concerning this fubjeft ; as of Fernelius, Snellif^Sy 
zndRiccipli ; and points ac the occafions of their refpe(3ive mi- 
ftakes delivering withal the DifFerences of their Meafures from 
his. Of the three, fVri^d'//^ comes the nighell: ; which M.Picart 
imputes to meer chance, fince he ufed not half the exaflnefs in 
obferving that did. S/^^Zf/'/i^ his difference from accurate- 
•nefs he attributes, i . To too final! a bafe, he took to meafure, and 
to too fmal I triangle?, which he was forced to take afterwards: 
To'the want of fo good Inftruments, as were employed in thefe 
Obfervacions. 
To adde fomething of the three Figures ; they reprefent the 
Connexion of Triangles, by which our Author meafur'd the Di- 
{idtnce froiw ^Jltalvoyjin to Sourdon^ and from Sour don 10 Amiens t 
From which meafure he concluded, what the juft length of a 
gree might be, reduced to the Parifian Toife. 
Concerning which Triangles nothing more needs to be added, 
but only a fuller Explication of what the Letters in them do fland 
-for; viz. 
A. the middle- point at the Mill of VUlejmfve. 
B4 the neareft corner of the Pavilion of Ivoify, 
C. the top of the Steeple of Brie Compe Robert. 
N n 2 D. the 
