VOL. LXXXVIII.] PHILOSOPHICAL TRANSACTIONS. 271 



And here I take an opportunity to announce, that the motion of the Georgian 

 satellites is retrograde. This seems to be a remarkable instance of the great 

 variety that takes place among the movements of the heavenly bodies. Hitherto 

 all the planets and satellites of the solar system have been found to direct their 

 course according to the order of the signs; even the diurnal or rotatory motions, 

 not only of the primary planets, but also of the sun, and 6 of their secondaries or 

 satellites, now are known to follow the same direction; but here we have 2 con- 

 siderable celestial bodies completing their revolutions in a retrograde order. 



I return to the examination of the miscellaneous observations, the result of 

 which has been of considerable importance, and will be contained in this paper. 

 The existence of 4 additional satellites of our new planet will be proved. The ob- 

 servations which tend to ascertain the existence of rings not appearing to be satis- 

 factorily supported, it will be proper that surmises of them should either be given 

 up, as ill founded, or at least reserved till superior instruments can be provided, to 

 throw more light on the subject. A remarkable phenomenon, of the vanishing of 

 the satellites will be shown to take place, and its cause animadverted on. I shall 

 now, in the first place, relate the observations on which these conclusions must 

 rest for support, and afterwards join some short arguments, to show that my 

 results are fairly deduced from them. For the sake of perspicuity, I shall arrange 

 the observations under 3 different heads; and begin with those which relate to the 

 discovery of additional satellites. A great number of observations on supposed 

 satellites, that were afterwards found to be stars, or of which it could not be as- 

 certained whether they were stars or satellites, for want of clear weather, will only 

 be related. 



Dr. H. first transcribes, from his journal, a number of reports and observations, 

 of a miscellaneous nature, some indicating suspicions of satellites, but mostly 

 showing only small fixed stars. These observations extend through several vears, 

 from Feb. 6, 1782, to March 25, 17Q7. On the whole Dr. H. makes these fol- 

 lowing remarks. 



An interior satellite. — The observation of Jan. 18, 1790, says, " a supposed 

 3d satellite is about 2 diameters of the planet following." There is not the least 

 doubt expressed about the existence of the satellite, or object in question, which 

 therefore must be considered as ascertained. Now the angle of the greatest 

 elongation of the Georgian satellites, by my new tables, at the time of observation, 

 was 81° 33' n. p. Therefore the angle of the apogee was 8° 27' s. p.; and since, 

 by observation, the satellite was " following," without any mention of degrees 

 being made, we may admit it to have been not far from the parallel; suppose 11 

 or 12° s. f. In this case, the satellite would be in the apogee about the time of 

 the 2d observation, at 7 h 57 m ; which says, " I cannot perceive the satellite." But 

 it will be shown hereafter, when I come to treat of the vanishing of the satellites 

 that it would become invisible in this situation. Indeed without the supposition of 

 the satellite's coming to the apogee, it might easily happen that the least change in 



