BIRLIOGRAPIIY OF HERSCIIHL's WRITINGS. 579 



Herschel, W.: Syxopsis of rui: \Vkitix<;s of— Contiuned. 



A. D. Vol. P. 



1801 91 :{1U-:U8 A f-cucial discussion ol' tlu; louclnslons to be deduced from the 

 observations quoted in this paper. [To Heusciiei, it seemed that 

 the absence of Openings, Ridges, and Nodules, indicated a scarcity 

 of luminous uuitter in the sun, and, therefore, that the seasons 

 duriu;; which such couditions of the sun were recorded ouglit to bo 

 of a lower temi>erature. He finds support for this view In tho 

 higher lu-ice of wlitnit during the live recorded i)criods of scarcity 

 of suu spots.] 

 318 Explanation of the 1st, xid, llth. and I'ith ligures of Plates XVIII 

 and XIX. 



1801 91 :?54 Additional Observations tending to investigate the S!jmptom>i of the rariahlc 



Emission of the Lijht and Heat of the Sun; with Trials to set aside dark- 

 ening Glasses, hg transmitting the Solar Bays through Liquids: and a 

 few RemarJcs to remove Objections that might be made against some of the 

 Arguments contained in the former Paper. By Willi.vm llKUscriEr., 

 LL. D., F. R. S. Read May 11, 1801. 



354-355 Considerations as to the relations of the condition of the solar sur- 

 face and the weather. 



355 "Before I proceed, I must hint to those who may be willing to attend 

 to this subject, that I have a strong suspicion that one half of our 

 sun is less favorable to a copious emission of rays than the other; 

 and that its variable lustre may possibly appear to other sohir sys- 

 tems, as irregular periodical stars are seeu by us; but, -whether this 

 arises from some ijermaneut construction of the solar surface, or is 



35G merely au accidental circumstauco, must bo left to future investi- 

 gation : it should, however, bo carefully attended to." 



356-361 Observations of the sun. 



361 Descrii)tion of a skeleton eye-piece, into the vacancy of which !uay 



be i)laced a moveable trough, shut at the ends with plain glasses, 

 80 that the sun's rays may be made to pass through any liciuid, suck 

 as spirits of wii4e, Port wine, mixture of ink and water, etc , placed 

 in the trough. 



362 Explanation of the Figures. Plate XXVIII. 



1802 92 213 Observations on the two lately discoveredbodies. [Ceres and Pallas.] By 



William Herschel, LL. D., F. R. S. Read May 6, 1802. 



213 \_Ceres'\ is of very small size. [Foot-note.] Its real diameter is not 



as great as three-eighths of our moon. 



214 Magnitude of the new Stars. \_Ceres and Pallas.] 



Ajiril 1, 1802. I placed a lucid disc at a considerable distance from 

 the eye and viewed with one eye tho magnitied star (seen with a 

 7-foot reflector) and the lucid disc with the other. 



215 By this means it appears that the real diameter of ('errs is not above 



0".40. 

 215 April 21. With a ten-foot reflector the same experiment gave 0". 38. 



217 April 2i. For Ceres the diameter was 0".22. For Pallas 0".17vand 



0".i:!. 



218 The real diameters arc, then, Ceres 161.0 miles, Pallas 147 miles. 



219 Of Satellites. [Observations on this subject.] 



220 There is certainly no satellite to Ceres that can be seen with the 20- 



foot reflector. 

 220 Of the Color of the neiv Stars. The color of Ceres is riuldy but not very 

 deep. Ceres is more ruddy than Pallas. Pallas is of a dusky whitish 

 color. 



