130 



PROCEEDINGS OF THE AMERICAN ACADEMY 



comparison with observation, the vahies of r derived from the periodic 

 equations of single period, the following corrections to Newcomb's 

 catalogue were obtained, viz. : — 



CORR. 



+.00* 

 a Andromedae, 

 a Arietis, 

 a Ceti, 

 a Tauri, 

 (3 Geminorum, 

 a Hydrae, 

 a Leonis, 

 j8 Leonis, 

 a Virginis, 

 a Coronas, 

 a Herculis, 

 c Lyrae, 

 a Pegasi. 



COHR. 



+.01" 

 /? Orionis, 

 /3 Tauri, 

 o Orionis, 

 a Canis Minoris, 

 a Bootis, 

 a- Librae, 

 a Serpentis, 

 a Ophiuclii, 

 y Aquilae, 

 /3 Aquilse, 

 a2 Capricorni, 

 a Aquarii. 



CORR. 



—.01"' 

 7 Pegasi, 

 a Scorpii, 

 a Aquilfe, 

 a Cygni. 



CORR. CORR. 



+.02* —.02* 



a Canis Majoris, a Aurigae. 



a Piscis Aust. 



The slight preponderance of positive corrections is due, partly to the 

 fact that only the nearest hundredth of a second was taken, and partly 

 to the fact that no account was taken of corrections depending on the 

 Declination. It wUl be found that there is a general tendency to posi- 

 tive corrections, when the corrections for errors of single period only, 

 are applied. The introduction of corrections for errors of double period 

 has a slight tendency to restore the equilibrium. It is only when the 

 corrections depending on the Declination are applied that the equinox 

 is restored to its original assumed position. 



In this discussion of late observations, the following data will be 

 employed : — 



(1) Greenwich. — The Greenwich Observations from 1858 to 1870, inclusive. 



(2) Washington, L — The Washington Observations from 1862 to 1870. The 



Right Ascensions given are found by applying the corrections to the 

 American Eplieraeris, given in the annual volumes. Tlie epoch for the 

 years 1862-3-4 is 1860.0. For the remaining years it is 1870.0. 



(3) Washington, II. — Tlie Washington Observations from 1858 to 1861. These 



observations, mostly made by Professor Yaniall, are purely differential, 

 and depend on the positions given in the Nautical Almanac for 1860. As 

 they show an excellent agreement inter se, their discussion will show 

 how far the periodic errors of the standard catalogue are transferred to 

 the observed. 



(4) Paris. — The Paris Observations from 1858 to 1866. 



(6) Melbourne. — The Melbourne Observations from 1858 to 1868. The places 



for 1860 depend on the observations of 1858-59-60. 

 (6) Brussels. — The" Brussels Observations from 1858 to 1866. 



