“ mg the value o f the quantities a, b, &c., and there is conic-
“ quently in the uncertainty o f the value o f thofe terms the germ
“ o f errors which would greatly exceed thofe which might arife
“ from the omiflion o f the other terms a”bnA . In all events,
m.n
“ U being already known, Q and are quantities which
“ ought to be firft determined, whether it ihould be afterwards
“ judged neceffary to carry the approximation farther or not.
'“ In one word, we ought, in all our calculations, which de-
“ pend on the figure o f the earth, to operate precifely as in our
“ calculations o f the motion of the heavenly bodies, whofe orbits
“ we firft iuppofe circular, then elliptical, and laft o f all we ap-
“ ply to -the former io corredted, the irnall equations which con-
“ tain the quantities in which the ellipies themfelves are defi-
“ cient. Such are the reafons entertained by the aftronomers o f
H all Europe for unanimoufly infilling on the neceffity o f new
“ meafurements, executed with all poffible care, with the affift-
“ ance o f the moll perfcdl inllruments, and according to the moil
“ approved methods o f obferving that the prefent age can fup-
“ ply. Now, the French aftronomers have juft finilhed the con-
“ ftrudtion o f a luite o f triangles, which as they pals through
“ France extend from Dunkirk all the way to Barcelona, a fpace
“ which forms an arch o f the meridian Q° 3q", or 10*. 7 2 , accord-
“ ing to the decimal lyftem. Nothing therefore could be more in-
“ terefting to all fuch as labour for the advancement o f aftronomy
“ and geography, than to hear that a committee has been ap-
“ pointed
“ pointed by government to determine the length o f an arch o f
“ the meridian comprehended between the parallel o f the North
“ Cape and that o f Upftad, or, at leaft, to meafure two or threer
“ degrees taken in the vicinity o f the polar circle. In the mean
“ time the academy o f fciences thought it might not be improper
“ to fend fome one o f its members to Tornea, in order to inform
“ himfelf as to the local circumftances.-of-the grounds which, in
“ 1736, were chofen by th e ' French mathematicians■ as< fixed
“ points, and the execution of' this plan was intrufted to mei I*
“ am now to give an account o f the remarks which I was cn-
“ abled'to'make on the fpot in regard to this fubjeil.
“ T he country in the neighbourhood o f Tornea is extremely
“ fla t; towards the north, however, and in that quarter only, air
“ the diftance o f eight leagues, more or lefs, there commences 3
“ chain, o f mountains which extends all the way to Kittifvaza;
“ near the fmall village o f Pello, from whence it becomes again
“ flat to the: diftance o f fome leagues beyond Kengis, which is-
“ twelve leagues north from Pello. In the whole o f thofe moun-
“ tains there is not one o f any eonfiderable magnitude : Avafaxa,
“ which I confider o f a mean fize, rifes only to the height o f fix'
“ hundred and'fix feet above the level; o f the river. From this itr
“ follows, that no one o f thofe mountains, confidered by itfelf/
“ could produce a lenfible deviation in the plumb-line, unlefs it
“ were very near one: o f the points where they determined ther
“ amplitude o f the arch o f the meridian, a circumftance which
“ has no place here. It remains then to know what might be the -
“ effedl: