288 



CATALOGUE OF POLAR STARS. 



We now have : 



da 



dt 



h. m. 



8. 



s. 



1875 7 29 5.6310 +73.5143 



1879 7 33 57.2480 +72.2895 



1883 7 38 43.9101 +71.0372 



1887 7 43 25.5157 +69.7626 



1891 7 48 1.9877 +68.4705 



1895 7 52 33.2626 +67.1655 



A 



1.2248 



1.2523 



1.2746 



1.2921 



1.3050 



A, 



A 



3 



8 



o / 



// 



+ 88 59 37.69 



- 0.0275 



+ 88 59 6.50 



+ 0.0052 



0.0223 



+ 88 58 33.76 



+ 0.0048 



0.0175 



+ 88 57 59.52 



+ 0.0046 



0.0129 



+ 88 57 23.81 



+ 88 56 46.68 



dt 



rr 



7.601 



7.993 



8.375 



8.746 



9.107 



9.458 



A 



1 



A, 



0.392 



+ 0.010 



0.382 



+ 0.011 



0.371 



+ 0.010 



0.361 



+ 0.010 



0.351 



Assuming +0 S .0044 for the third difference of 



7 & 



for the second difference of — , we have : 



dt 7 



da 

 dt 



pposite 1893, and + 0".010 



d 



dt 



s. 



Tl, 771. 8, 



1891 7 48 1.9877 +68.4705 



1895 7 52 33.2626 +67.1655 



1899 7 56 59.3003 +65.8520 



1903 8 1 20.0768 +64.5342 



1907 8 5 35.7067 +63.2161 



A 



1.3050 



1.3135 



1.3178 



1.3181 



A 



A 



8 



8 



o / 



rr 



0.0129 



+ 88 57 23.81 



+0.0044 



0.0085 



+ 88 56 46.68 



+ 0.0042 



0.0043 



+ 88 56 8.17 



+ 0.0040 



0.0003 



+ 88 55 28.32 



+ 88 54 47.17 



dS 



dt 



rr 



9.107 



9.458 



9.798 



10.128 



10.448 



A 



A 



+ 0.010 



0.351 



+ 0.011 



0.340 



+ 0.010 



0.330 



+ 0.010 



0.320 



After proceeding thus far, it will be advisable to recompute the values of 



, and the resulting values of a and S. Then, with the more accurate 

 series of differences, the computation for several intervals in advance can be safely 



da , dd 



~ and 



dt 



dS 



made. It will be found that the values of S and — require no change. 



For 



da 



a and — we find: 



dt 







