IN THE ARCTIC SEAS. 



13 



Reduction of Preceding Transits. 



There being no level readings, the amount of inclination of the transit axis has 

 to be found from the transit observations themselves ; the number of unknown 

 quantities in the normal equations, however, could be reduced to three, since the 

 coUimation error could be deduced independently. The instrument was adjusted 

 for collimation on November 18, and on December 13, Polaris was observed, 

 reflected, circle east and circle west, from which observation the collimation has 

 been deduced ; the result was, however, satisfactorily checked in those sets of 

 observations, including stars above and below the pole. A preliminary reduction 

 was made in order to ascertain an approximate value for the rate of tlie chronome- 

 ter ; this instrument was considered as a sidereal chronometer with a large rate. 



The following notation has been used in the reduction. 



a = azimuthal deviation, iu seconds of time | ,- 



^4 = azimuthal factor ; correction for azimuthal deviation Aa. 



when instrument is 



( east ) 

 \west j 



of south. 



b = inclination of axis, in seconds of time \^\- , when -> "^^^^ \ end is high. 



( east 7 



■)_ — ]' ' """=" ^east j 

 B = level factor ; correction for level Bb. 

 c = collimation error, in seconds of time ; forupper culmination |2_| when meau ot wires is ^^^^.^^j- 



of line of collimation. 

 C = collimation factor ; correction for collimation Cc. 



