C 3 
The principal Inftmment M. Cajpni carried with 
him, was, a Limb of 12 Degrees, whofe Radius was 
indeed 10 Foot, but divided only into Degrees and 
Minutes 5 the other Parts were added to it 
Here Mr. Celfius obferves, that the finding 
the true Centre of this Limb was and fliil is a very 
difficult and troublefome Problem to a good Artift^ 
that no mention is made, whether the Pofition or 
place of this Centre, and the Divifions of the Limb, 
were ever examined at Varis or Colliourej though 
the Carriage of the Inftrument through fo long and 
rough a Way, could not but make fome Alteration in 
the Place of the Centre. 
It is true, the Zenith Diftance of Capella^ taken by 
it at TariSy was confirmed to be right by another 
Inftrument j but it cannot be concluded, that the 
Zenith Diftance of the fame Star, taken at Collioure 
by this Inftrument, and not confirmed there by an- 
other Inftrument, muft be true alfo. For the Point 
of Divifion, anfwering to this Diftance in the Limb, 
was not examined ; and a Centre wrong placed may 
by Accident give the true Zenith Diftance, <viz* when 
the true and erroneous Centre happen to lie in the , 
fame Perpendicular to the Horizon. 
The Exceptions taken to the Aftronomical Obfer- 
vations for finding the Difference of Latitude be- 
tween Tans and Collioure, are, in the firfl: place. 
That though Five Stars were obferved at Collioure and. 
Tarts, yet One only was made ufe of, viz. Capella: 
That the Difference of Latitude by Capella is 6^^ 18' 
57": If Lucida Lyra had been ufed, the Difference 
would have been but 6^ 17' y " but by the Right 
Shoulder of Auriga^ 6 ° 19^ 25'': Hence arifes the 
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