3i8 Meafure of the Meridian in France, is'c. 



elude, after the refearches of the celebrated La Caille, that the mean degree wouLl not differ 

 tfiuch from S7027 toifes ; and confequently that the fourth part of the meridian would con- 

 tain 5,i2j,420, and that the ten millionth part of this arc would be 443,443 lines. In the 

 juft impatience to enjcy the great benefit of exaft, uniform, and univerfal meafures, the length 

 of the metre was provifionally fettled at 443,44 under the well-formed perfuatioii that the 

 more precife determinations, which were to be expedled, would produce but a flight change 

 in this magnitude. 



Nevcrthelefs, tlie academy, which confidered this fubjec'!^ in its true point of view, as well 

 in its general as in its particular relation, with regard to the public utility, its intiiriate con- 

 nexion with the moft important points of phyfical aftronomy, with the national reputation, 

 to which it was of confequence that the foundations of a new metrical fyftem, propofed to a 

 great people, and prefented to the whole world for their adoption, fhould be determined with 

 the greateft precifion, conceived the great projedl of obtaining a new meafure of the meridian 

 which crofles France, by extending it beyond the frontiers, as far as Barcelona, and to apply 

 this great arc to determine the fourth part of the earth. The conftituent affembly adopted 

 this vaft projecl:, and entrufted the execution to the academy, which nominated, without 

 delay, feveral of its members to employ themfelves on the different parts which cortipofed 

 the totality of the metrical fyftem -y and laftly, they charged the Citizens Mechain and De- 

 lambre, (o worthy, in every refpeiH:, of this honourable, though laborious mi (lion, with the 

 ta{k of meafuring the meridianal arc. The Inftitute afterwards nominated Cit. Lefcvre 

 Gineau to make the experiments relative to the determination of the uaity of weight ; and 

 he has proved, by the beauty and accuracy of his work, how truly deferving he was of being 

 aflbciated with his illuftrious bretlvren of the academy. 



This great and important operation, projeiSled by the academy of fciences for the eftablifli- 

 ment of a new metrical fyftem, began by their orders, and happily terminated under the auf- 

 pices of the inftitute, after feven years' labour and care, is in many refpeits deferving of re- 

 mark. It is fmgular for the' extent of the terreftrial arc, which being more than nine de- 

 grees and two thirds, furpaffes all thofe which have been meafured ; — for the extreme exaft- 

 nefs with which all the parts have been executed i the terreftrial furvey for determining the 

 length of the arc; the aftronomical obfervations ; the operations for fixing fhc- unity of 

 weight; the experiments On the length of the pendulum ; all thefe have proceeded together, 

 and each has been treated with the fame precifion; and laftly, it is remarkable, and perhaps 

 without parallel, for the degree of authenticity with which it is fanftioned. In faiSt, the 

 Inftitute has defired not only that commiflioners chofen from its own body ftvould examine 

 every tiling that is done, but likewife that learned foreigners fhould join, and make it a com- 

 mon work. The gctvernment has feconded this wifti, by inviting the allied or neutral 

 powers to fend deputies for this object. Several have accepted this invitation ; and thefe depu- 

 ties, joined to the French commiflioners, compofed the commiflion of weights and meafures*, 



which 



* The following is an alphabetic lift of the names of the members of the commilTion of weights. ■ ^ncse, 

 from the Batavian republic ; Balbo, deputy from th« lung of Sardinia, afterwards replaced by Cit. ValTali ; 



Bocda, 



