BIBLIOGRAniY OF HEUSCUHl's WRITINGS. 579 



Herschel W.: Synopsis of tmk Wi:itix<;.s ok — ContiiuuMl. 



A. D. Vol. P. 



1801 91 310-318 A goiHTiil discussion of Mio coiicliisions to bo deduced from the 

 observations quoted iu this pajxT. [To IIkusciiel it seemed that 

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

 of luminous nuxtter iu the sun, and, therefore, that the seasons 

 during which such conditions of the sun were recorded ought to bo 

 of a lower temperature. He iinds support for this view iu tho 

 higher price of wlu^at during th(^ live recorded i)criods of scarcity 

 of sun spots.] 

 318 Explanation of the 1st, 'Jd, 11th. and I'ith figures of Plates XVIII 

 and XIX. 



1801 91 354 Additional Observalioiis tcndimj to investigate the SiimptoinH of the variable 

 Einmion of the Light and Heat of the Sun; with Trials to set anidc dark- 

 ening Glasses, hy transmitting the Solar Puiiis through Liquids; and a 

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

 Arguments contained in the former Paper. By William Hf.usciikl, 

 LL. D., F. R. S. Read May 14, 1801. 

 354-355 Considerations as to the relations i)f the con<lition of the sohir sur- 

 face and the weather. 



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



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

 suu is less favorable to a copious emission of rays thau the other; 

 and that its variable lustre may possibly appear to otlier solar sys- 

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

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



356 merely au accidental circumstance, must be loft to future investi- 

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



356-361 Observations of the sun. 



361 Description of a skeleton eye-piece, into the vacancy of which may 



be placed a moveable trough, shut at the ends with plain glasses, 

 80 that the sun's rays may be made to pass through any liquid, such 

 as spirits of wine. 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 discovered bodies. [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 netv Stars. \_Ceres and Pallas.'\ 



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

 the eye and viewed with one eye the magnified star (seen with a 

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



215 By this mo* ns it appears that the real diameter of Ceres is not above 



"o".40. ,, , 



215 Apiil 21. With a ten-foot reflector the same experiment gave 0' . 38. 



217 April 22. For Ceres the diameter was 0".22. For Pallas 0".17 and 



0".13. 



218 The real diameters are, then, Ceres 161.6 miles, Pallas 147 nules. 



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 ruddy but not very 

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

 color. 



