604 



SCIENTIFIC RESULTS OE ZIEGLER POLAR EXPEDITION 



TIME AND LONGITUDE 



On account of the sticking of the micrometer screws in the extreme cold weather time was 

 determined by star transits in preference to measuring star altitudes. These transits have been 

 reduced by the usual method of least squares.* In connection with time observations, deter- 

 minations of longitude were made during the winter of 1903 to 1904 by observing transits of 

 the moon. This method was adopted in preference to the chronometric method in view of the 

 small number of chronometers carried by the Expedition, these also being subject to many 

 heavy shocks in navigating in the ice and exposed to very great changes of temperature. 

 Numerous other complete transit sets were observed and reduced, but in view of the fact that 

 they have been used primarily in the determination of corrections simply to local time, they are 

 not published. The equatorial intervals of the reticule as determined from observations and 

 used in the reduction of the various transit observations are as follows, the signs applying for 

 ' ' clamp east ' ' : 



Text-book of geodetic astronomy, by John F. Hayford. New York, 1898. 



