176 DOOLITTLE—ORBIT OF DOUBLE STAR 2 518. _[Aprils, 
The residuals from these elements were not wholly satisfactory, 
especially between the years 1853 and 1879, when they steadily 
maintained the positive sign. For the purposes of a further im- 
provement, therefore, the original observations were next grouped 
into the following thirty-three normal places : 
Date. p. 6. n. Observer. 
! 
4/ ° 
1850.94 3.96 156.6 2 \OiSr 
1851.28 z.50. | 156.7 3 O. S., Da 
1853.64 3.93 158.3 3 O..S. 
1854.79 4.13 155.3 i rf 
1856.80 4.51 152.9 I SOF 
1857.82 4.40 153.0 I ce 
1864.84 4-45 147.6 2 Wi., 
1865.89 4.26 144.0 2 OS 
1869.10 4.46 140.4 I s 
1871.99 2 125+ I Kn, 
1872.56 4.62 140.6 1-2 O.S. 
1873.99 4.27 133-9 I ff 
1874.10 4.39 Va5o7 I Ke 
1875.14 3.80 138.1 I BS 
1876.11 4.01 130.5 I a 
1877.86 3.80 Reyes II D, GOs 
1878.14 4.36 125.5 I OS: 
1879.09 3.50 125.3 6 B., Ha. 
1880.52 3:22 121.6 10 B 
1881.84 3.53 119.0 6 is 
1382.12 3.25 118.2 2 Ha. 
1883.40 3.09 117.5 4 B., Ha. 
1884.16 3.74 118.2 I Hi. is. 
1886.30 3.04 II1.9 II bP ts Be be 
1888.51 2.95 106.7 II Ha:s B. ike 
1889.12 2.79 103.6 4 -Ha 
1890.84 21247 99.6 7 B., Ho. 
1891.38 PE) 98.1 9 B:, Ea. 
1893.21 2.18 93-8 I Com. 
1895.90 2.32 85.5 I-2 DIAG. 
1897.97 2.62 Chie 3 A. 
1899.53 2.34 70.4 5 A., Doo. 
1900.92 2.40 63.4 2 Doo 
These measures were corrected for precession, and to the result- 
ing 33 equations there were assigned two series of weights, the 
first depending only on the number of nights, and the second being 
