590 BIBLIOGRAPHY OF HERSCIIEL^S WRITINGS. 



Herschel, V/.: Synopsis of tiii': AVritings of— Contiuncd. 



A. D. Vol. p. 



180G 9') 2'55 The result of calculations founded on facts, such as we must admit 

 the proper motions of the stars to be, should give us useful infor- 

 mation, to satisfy the inquisitive mind or to lead us on to new dis- 

 coveries. The establishment of the solar motion answers both 

 these ends. Our inquiries should not terminate here. A pai)er on 

 general Gravitation [by Dr. Wilson] with what is said here, xmts 

 us withiu reach of a link of the- chain which connects the iirinci- 

 ples of the solar and sidereal motions with those which are the 

 cause of so many orbitual ones. 



236 What has been said before of the Sun as an insulated star does not 



contradict the iiresent idea of its making oue of a very extensive 

 system. 



237 The insulation refers merely to a supposed binary combination with 



some neighboring star. 



180G 96 455 Observations and Bemarlcs on the Figure, the Climate, and the Atmosphere 

 of Saturn and its Eing. By William Herschel, LL. D., F. R. S. 

 Read June 26, 1806. 



455-457 [Account of Herschel's observations on the figure of the ball.] 

 Plate XXI, Fig. 1, represents Saturn in 1789, and Fig. 2, in 1805, 

 May 5. 



458 To discover the flattening of the figure of the ball a high magni- 

 fying power (500) was necessary. A lower jjower will afterwards 

 show it. No error could arise from the defalcation of light May 6, 

 1805. 



459-464 Observations of the figure of Saturn. 



462 The flattening at the poles of Saturn is more extensive than on Jupiter. 

 The curvature in high latitudes is also greater. At the equator it 

 is rather less. Upon the whole the shape of the globe of Saturn is 

 not such as a rotatory motion alone could have given it. 



462 1806, June 3. The shadow of the ring on the ball is broader at the 



ends than in the middle. 



463 The breadth of the ring is to the space between the ring and the ball 



as about 5 to 4. The ring appears to be sloping towards the ball. 



463 The shadow of the ball on the ring is not parallel with the outline of 



Saturn. 



464 Observations on the periodical changes of color of the polar regions of 

 Saturn. In the observations of Mars {Phil. Trans., 1784, p. 260) it 



has been shown that a periodical change takes place in the extent 

 and brightness of the polar spots. I have suggested that this may 

 be due [to frozen regions at the poles, varying in aize as they aro 

 more or less exposed to the Suu.] 

 The following observations may lead to similar conclusions with re- 

 spect to Saturn. 

 466 The gradual change of color of the polar region during a Saturnian 

 year seems to be in a great measure ascertained. This can only be 

 confirmed by a long series of observations. 



466 On the atmosphere of Saturn. 



From observations wo may infer the existence of a Saturnian atmos- 

 phere. 



467 A probability that the ring of Saturn has an atmosphere has been 



pointed out in a former paper. 

 [Dated] Slough near Windsor, June 12, 1806. 



