240 History of Astronomy for the Year 1805. 
measured at 3°, but reduced to zero, we must take from it 
eight toises: this augments the difference by eight toises, 
The former, in ede of 57419, becomes 574225. and the 
second reduced to 111462 metres, makes 57200 toises: thus 
there are 222 toises too much. As this agrees with the other 
degrees measured, and with the oblatencss given by the pen- 
dulum and the moon’s parallax, we cannot refrain from 
adopting the new resuit, although it is difficult to compre- 
hend how our academicians in 1736 came to commit so great 
anerror. The Swedes thought that the sector of nine fect 
was more liable to be deranged, and less certain, than the re- 
peating circle which they made use of. 
M. de Zach has examined the work of the Swedes: he 
compared the angles, and the reductions: he finds the re- 
duction payers but the work is not less important or 
beneficial. 
In order to clear up the enormous differences between the 
measurement of the French and that of the Sites I observe 
four things. 
1. The sector was not reversed: this was too difficult. 
2, The wire was suspended by astud upon a thickish cy= 
Iinder; and there might be friction. 
It was not then known how important it was that the 
optic axis of the telescope should be parallel to the plane ; 
two lines of difference in the position of the glasses make 
six minutes upon a radius of nine feet, and this difference 
may thence arise; there may result from this upon the di- 
stance to the zenith an error so much the greater, as pro- 
bably the glass was directed_to the stars by their transits to 
the meridian, and not by a meridian wire. 
4. | remember extremely well that Maupertuis told me 
“that he was anxious to recommence the measurement. 
We have also seen in the London Transactions that Mudge 
as measured three degrees in England. He found 111189 
metres at 52°; this agrees with the French measurements : 
but he found for the ieott part 164 metres less than for the 
south part, and he ought’to have found 23 metres mores 
which announces irregularities in the interior structure of 
the earth and in the attractions of mountains, and which 
makes: — 
