124 Observations relating to the Operations underlaken 
repeated the same operations upon different points of the are 
comprised between Perpignan and Dunkirk. These experiments 
gave for the flattening of the earth a value almost equal to that 
which M. Delambre had already obtained, by comparing the 
are of France and Spain with the degrees of the equator, but 
calculated with more accuracy, and corrected by the degree of 
Lapland, which Mr, Svanberg, an able Swedish astronomer, had 
certified by new observations; and finally, with an are of many 
degrees which Major Lambton had measured with great accu- 
tacy in the British possessions of India. 
Confirmed by so many combinations, our are of France and 
Spain had a good title to become a fundamental model for mea- 
sures. An occasion occurred of rendering it still more impor~ 
tant. Since the rebellion of 1745, the English government had 
perceived the utility of constructing a detailed map of the three 
kingdoms, which should equally serve to direct the amelioration 
of the country in peace and its defence in war. I may state, in 
passing, that it is the war for twenty years back which has given 
to geodesiacal operations the great extension and the extreme 
perfection which they have acquired in all the states of Europe. 
However this may be, the English triangulation begun by Ge- 
neral Roy, and continued after him by Colonel Mudge, was pro- 
longed from the south of England to the north of Scotland, and 
presented in that extent many degrees of the terrestrial meri- 
dian measured with excellent instruments. It was desirous that 
this are should be joined to that of France. But as from the 
geographical position of England she is placed a little to the 
westward of ours, there was reason to fear, lest, all the terrestrial 
meridians not being exactly alike, the difference of longitude 
would affect the results which might be obtained from that 
junction. Nevertheless, there could be no dread of this, so far 
as concerned the measurements of the pendulum, which are 
much less disturbed than the degrees by the slight: irregula- 
rities of the figure of the earth. The Board of Lougitude was 
desirous that the same apparatus which had served for these 
measurements in France and Spain, should be employed through 
the whole extent of the English arc. The consent of govern- 
ment and the approbation of men of science in England were 
necessary. Neither the one nor the other was wanting. ‘The 
respectable Sir Joseph Banks and his worthy friend Sir Charles 
Blagden assured us of all imaginable facilities. M. Lainé the 
minister of the interior, with whom every thing useful or honour- 
able has only possibility for its limits, was able to furnish means 
for this enterprise, and the Board of Longitude had the good- 
hess to intrust me with its execution, 
1 left 
