VI CONTENTS. 



Astronomic determinations of position — Continued. Page. 



Observations for latitude 21 



Reduction of observations for latitude 23 



Measurement of a division of the head of the micrometer screw 23 



Measurement of a level division ^ 26 



Computation of apparent declination of stars 27 



Computation of latitude 28 



Observations for time 28 



Reduction of time observations 29 



Correction for error of level 29 



Correction for inequality of pivots 30 



Correction for error of collimation 30 



Correction for deviation in azimuth 30 



Correction for diurnal aberration 31 



Comparison of time 34 



Observations for azimuth . . . . : 36 



Reduction of observations for azimuth 38 



Chapter III. 



Horizontal location 41 



Party organization 41 



Base line measurement 42 



Reduction of base line measurement 45 



Reduction to standard 45 



Correction for inclination 46 



Correction for temperature 46 



Reduction to sea level 46 



Primary triangulation 48 



Selection of stations 49 



Signals 50 



Heliotropes -• 52 



Theodolites for triangulation 54 



Instructions for the measurement of horizontal angles 55 



Organization of parties and prosecution of work 63 



Reduction of primary triangulation 65 



Reduction to center 65 



Spherical excess 65 



Station adjustment 66 



Figure adjustment 68 



Computation of distances 72 



Computation of geodetic coordinates 72 



Traverse lines for primary control .• 75 



Primary elevations '■ 77 



Chapter IV. 



Secondary triangulation 79 



The plane table 79 



The alidade 82 



Measurement of altitudes 84 



