166 
SECOND REPORT— 1832 , 
In the years 1801, 1802, 1808, the arc measured in Lapland 
(which, according to the calculations of Clairaut and Mauper- 
tuis, seemed to present a strange anomaly,) was remeasured and 
extended by Ofverbom, Svanberg, and others, so as to embrace 
an amplitude exceeding \\ degree. For the geodesic part, as 
well as for the astronomical determinations, the new repeating- 
circle was used. The conclusions at which they arrived dif¬ 
fered from those of Maupertuis, and are more in accordance 
with those given by other measures. But they did not succeed 
in pointing out the cause of their difference ; and, as far as their 
measures admitted of comparison, they confirmed greatly the 
accuracy of the former measure. The former measure has 
lately been much discussed, especially by M. Rosenberger in 
various numbers of the Ast. Nadir . ; and the general opinion I 
think is now, that the first measure was the best, and that its 
anomaly depended only on the ruggedness of the country. In 
the Phil. Trans. 1803, is an account of the English measure of 
an arc from the south-eastern part of the Isle of Wight to 
Clifton in Yorkshire. The bases were measured with Ranis- 
den’s steel chain, and the horizontal angles with a large theo¬ 
dolite : the astronomical observations were made with Rams- 
den’s zenith-sector. There is no doubt that, for its length, this 
was the most accurate arc that had been measured. Yet a 
point near the middle of this arc presented an anomaly in re¬ 
gard to the direction of gravity. The measure was afterwards 
extended to Burleigh Moor: and it thus comprehends an arc 
of nearly four degrees. Two arcs (of which the details are to 
be found in the Asiatic Researches,) were measured by Colonel 
Lambton in India. The first of these, near Madras, was of 
1 \ degree : the other, beginning near Cape Comorin, nearly 
10 degrees. The latter has lately been extended by Captain 
Everest to nearly 16 degrees. The methods adopted in 
these measures differ in no respect from those of the English 
measure : and this arc is undoubtedly the best that has ever 
been surveyed. The French arc from Dunkirk to Barcelona 
has been extended by Biot and Arago to the little island For- 
mentera in the Mediterranean (near Xviza), and its vdiole length 
is now nearly 12^- degrees. Of the excellence of the geodetic 
part of this there is no doubt; but there seems some reason to 
doubt the goodness of the astronomical determinations, though 
no labour v T as spared by the observers. The account of this 
forms a conclusion to the Base du Systeme Metrique. The 
Piedmontese arc of Beccaria has been remeasured with much 
care by Plana and Carlini: and the account is published in the 
Operations Geodesiques et Astronomiques en Piemont et Savoie. 
It is clearly proved that the astronomical part of Beccaria’s 
