BIBLIOGRAPHY OF IIERSCHEL's WKH'INGS. 587 



llersciiel, W.: Syxopsis ok tuk Wmrixcs OF— Coutiimcd. 



J.. D. Vol. p. 



£.t>95 95 236 Si/mptoms of parallactic Motions. 



Three sorts of motions expluiiu-d hy Fi<;. 1, Plat*; VII. 

 237 The parallactic, the real, and the apparent motions. 

 ^38 Since a motion of the sun will occasion parallactic motions of the 

 stars, these again must indicate a solar motion. To ascertain 

 whether parallactic motions exist we must choose the brightest 

 stars which are most attected by solar motion, they being probably 

 the nearest to the sun. 

 '238 We distinguish parallactic from real motions by the direction of 

 the motion. If a solar motion exists all parallactic motions will be 

 opposite to it; real motions will be dispersed indiscriminately to 

 all partis of space. 

 •239 The point towards which the sun moves is the apex of solar motion; 

 the opposite point is the parallactic centre. 



240 Table I. Ten jiositious of the solar apex from iirst magnitude stars. 



241 Fifteen positions from fainter stars stated. 



242 Changes in 'he position of double Stars. Among the 56 stars which I 



have given, the changes of more than half appear to be [due to a 



solar motion]. 

 242 Incongruity of proper Motions. 

 242 Sidereal occultation of a small Star. 



As far as we can judge at present the vanishing of the small star near 



S Ci/gni is only a parallactic disapjiearance. A real motion would 



also explain it. 

 244 Direction of the Solar Motion. 



248 When we are in search of an apex for the solar motion, it ought to lie 



so fixed as to be equally favorable to every star. * * * Our aim 

 should be to reduce the proper motions of the stars to their lowest 

 quantities. 



249 Table II of the direction and qiiantity of the apparent motion of sis 



stars, supposing the sun to move towards X Herculis. 



251 Table III of the angles of the parallactic motion with the parallel ; 



and Table IV, angles of the apparent with the parallactic motion. 



252 Table V. Quantities and sum of the least real Motions. 



253 Assuming the apex of solar motion to be in R. A. 270° 15', N. P. D. 



54° 45', Table VI is computed : it is similar to Tables III, IV, V. 



254 Assuming the apex R. A. 245° 52' 30", N. P. D. 40° 22', Table VII 



[like Table VI] is calculated. 



255 Although the great pi-oper motions of Arctarnn, Proci/ou, and Sirius 



are strong indications of their being affected by parallax, it is not pro- 

 bable that their apparent changes are entirely due to solar motion. 

 25(5 Observation shows that proper motions do exist : we should choose 

 that apex which will take away more real motion than any other, 

 or we shonld put the apex in R. A. 245° 52' 30", N. P. D. 40^ 22'. 



1805 95 272 Observations on the singular Figure of the planet Saturn. By Wu.Li.vM 

 Herschel, LL. D., F. R. S. Read June 20, 1805. 

 272 [Brief account of the particularities of the system of Saturn. '\ 



272 There is a singularity left which distinguishes the figure of Saturn 



from that of all the other planets. In 177G I perceived that the 



273 body of Saturn was not round. In 1781 I found it was flattened at 

 the poles more than Jupiter. In 1789 I measured the polar and 

 equatorial diameters, and prepossessed with the idea of its being 

 spheroidical I [paid no attention to other diameters]. 



