588 BIBLIOGRAPHY OF HERSCTIEL'S WRITINGS. 



Herschel, W.: Synopsis of the Writings of— Coutiimed. 

 A. D. Vol. P. 



1805 95 2-7:! Observatious on Saturn: [from 1805, April 12, to June 2] 1805, April 



12. The ring is brighter than the body, and whiter. 



274 April 18. The figure of Satu7-u is different from the spheroidical figure 



o{ Jupiter. Tlie 4 points of g>-eatest curvature are in latitude 4G^ 

 38'. 



275 The shadow of the ring on the body is broader at the ends than in the 



middle. 

 275 April 19. The figure of Sulurn is like a parallelogram with the four 

 corners rounded off deeply. The latitude of the four points of 

 greatest curvature is 45° 44'. 5. 

 276-277 May 5-13. Saturn amlJupiler were viewed alternately [and the 

 preceding remarks confirmed]. 



279 The real Saturn compared with the figure in Phil. Trans., 1790, p. 17. 



The two did not agree. I then modified the latter and made them 

 agree. An exact copy is given in Plate IX. 



280 Dimensions of the parts given. 



1806 96 205 On the Quantity and Velocity of the Solar Motion. By William Her- 



schel, LL. D., F. R. S. Read February 27, 1806. 



205 The direction of the solar motion was ascertained in a former paper: 

 the A^elocity is now in question. 



205 The proper motions, reduced to one direction, have been called quan- 

 tities, to distinguish them from the velocities of the moving stars, 

 required to produce those motions. The same distinction must be 

 kept with respect to the velocity of the solar motion. 



205 At a given distance, when the quantity of the solarpiotion is known, 



its velocity is known, and every approximation towards a knowl- 

 edge of the distance of a star of the first magnitude will be one 

 toward a knowledge of the real solar velocity. It is otherwise with 

 a star, for the angle of the direction of its motion with the visual 

 ray is unknown. 



206 I shall use the former six stars in the present paper. 



206 Proportional distance of the Sfais. 



207 I jjropose the following arrangement: Table VIII, proportional Dis- 



tances of Stars ; Sirius, 1.00; Arcturus, 1.20; Capella, 1.25; Lyra, 1.30; 

 Aldeharan and Procyon, 1.40. 



208 I have tried all the known and many new ways of measuring the com- 



parative light of the stars, and no one gives a satisfactory result. 

 When we have more authentic data, the calculation may be re- 

 peated. 



208 Effect of the increase and decrease of the Solar Motion and Conditions fo 



be observed in the Investigation of its Quantity. 



209 Table IX. In 6 columns : Stars ; Apparent motion ; Solar motion ; 



Parallactic motion ; Real motion ; Velocities. 



210 It is not the motions but the velocities which must be equalized. 



211 It is assumed that their real motions are at right angles to the visual 



ray. [The objection to this considered.] 



213 Calculations for drawing Figures that will represent the observed motions 



of the Stars. 

 These are of two classes ; the first will remain unaltered whatsoever 

 the solar motion ; the second must be adjusted to every change 

 [of solar motion]. 



214 We must assume relative distances for i he rest of our stars. 



