OBSERVATIONS. 



clvi 



G. OBSERVATIONS OF MARS I. WITH THE CAMBRIDGE EQUATORIAL. 



A comparatively large number of observations of right-ascension only are given in the present 

 volume; as these however not only have no relation to the problem before us, but are incapable, 

 under any circumstances, of furnishing a trustworthy value for the parallax, (s. Astronomical 

 Journal, N. 103,) they have not been critically examined. To the observations for declination 

 the following corrections or modifications have been applied : 



Page 453, November 15, 16. The "unknown star" is the comparison-star of the preceding day. (Bessel Z. 348.) 

 454, " 16, 17. The comparisons were evidently with the south limb, not the north. 



457, December 17. Mean M,for 3' 34". 69 read 0' 34". 69. 



458, " 27. The planet was smith of Bessel Z. 405, not north. 



458, " 29, 30. There is some undetected error here. 



459, January 1. The comparisons are neither accordant with one another nor with the mean. The second 



series, upon reduction, gives A<! = 0' 34". 10 0". 02 = 0' 34". 08 ; but evtn then the 

 difference between the north and south limb is nearly twice the diameter of the planet. 

 The comparisons will, if used as follows, give nearly the average accordance with the 

 Ephemeris : 



Mars, S. limb, N. of Bessel 405. 

 Corr. Sid. time. Microin. 



Adopted 

 zero. 



53r.428. 50r. 034. 



460, 



4CO, 



Chron. Corr. Sid. time. 



1A. 54m. 40s 8. 59s. 4. U. 53m. 41s. 4. 



and the values have been assumed. 



1 5, results, line 1, Mean &t, for 1' 45". 10 read 2' 4''. 10. 



3, " " 1 45 .01 " 2 4 .01 



1 5, " 3, Microm. " Sr. 394 " ISr. 394 



Micrometer 

 Rev. Arc. 



3r. 394 33". 26 



Corr. A<i 



0. 02 33. 24 



The Cambridge series will then be as follows : 



MARS I. 



Observations with the Cambridge Equatorial. 



