2 



ASTRONOMICAL OBSERVATION* 



The intervals are quite unequal, but the reduction of the mean of all the wires to the 

 central wire is no greater than when the instrument was first received, being Os.107 x 

 secant of the declination ; positive above the pole, and negative below. I have therefore 

 not attempted to change the position of the lines, as with a proper method of reduction 

 the inequality of the intervals does not affect the accuracy of the observations. The 

 pendulum of the clock appears to be somewhat under-compensated, — its daily rate being 

 about one-second slower in summer than in winter. 



I. LATITUDE OF HUDSON OBSERVATORY. 



During the summer of 1841, I observed twenty-four culminations of Polaris; in 1842. 

 fifteen culminations of Polaris, and four of (3 Ursa? Minoris; and in 1843, fifteen culmina- 

 tions of Polaris. They were all made in the usual way, alternately direct and by reflexion 

 from mercury. The errors of the microscopes were found to be as follows: 



The places of the stars are taken from the Nautical Almanac, and require corrections. 

 In the Almanac for 1843, the declination of Polaris is corrected + 0".50 to conform to 

 the Greenwich observations, and in that for 1844, the correction is given + 0".38. Ac- 

 cordingly, the declinations of the Almanac for 1841 and 1842 have been increased 0".38, 

 and those for 1843 diminished 0".12. In the Almanac for 1842 the declination of 

 (3 Ursse Minoris is corrected — 0".90, while the Almanac for 1844 gives the true correction 

 — 0".46. The declination for 1842 has accordingly been increased 0".44. 



The following arc the results of the observations: 



Lower culmination of Polaris, 



