21 



of October, and on the 2nd instant ; and I found tliat all the observa- 

 tions were well satisfied, for so short an interval, by a period of revolu- 

 tion of four days for the outermost and two days and five-tenths for the 

 innermost. They are most minute objects, having probably much less 

 than lialf the brightness of the second and fourth, (the two conspicuous 

 ones,) though on the 2nd instant the whole four appeared at once in my 

 telescope, charged with a power of 778 times. I enclose diagrams of 

 the configuration of the satellites as they appeared on each of the four 

 nights above mentioned. 



For the infonuation of those not conversant with these minute objects, 

 I may state that Sir William Herschel attributed to this planet six 

 satelUtes, of which the two first were discovered on or about the 9th of 

 February, 1787, (Vide Phil. Tmns. for that year); and in the Phil. 

 Trans, for 1798 he gave an account of the discovery of four additional 

 satellites. Sir William Herschel has also a further paper on the same 

 subject in the vol. for 1815. Of these six, only the first two have ever 

 been certamly recognised by any other observer, so far as I am informed. 



On the 12th instant I again saw these two new satellites, along with 

 the old bright ones, though in such an unfavorable state of the sky that 

 I was only able to obtain a single measure of the one marked III., and 

 estimations of positions of the others. 



With these data I calculated the positions for the 12th of November 

 to be severally: IV.= 2°, III.= 115°, II.= 99°. and I.= 330° (II. 

 and I. being the newly discovered satellites.) Their observed positions 

 were: 1V.= 5°, III.= 112°, II.= 131°, and I.= 332°, which gives a 

 period of 4,150 days for II., and 2,506 for I. These seem to me to be 

 as satisfactory as could possibly be anticipated, and sufficiently establish 

 their elements for future recognition at the very least. 



Opportunities have not yet been afforded me of obtaining accurate 

 measures of the distances of these satellites from Uranus, but such 

 estimations as I have been able to make agree sufficiently well with 

 the theoretical distance which the observed periods give. 



It is evident that these newly discovered satellites are closer to the 

 planet than any of Sir William Herschels six, the nearest of which had 

 a period assigned to it by him of 5 days and about 21 hours. 



I have to apologize for the hasty manner in which this account is 

 drawn up. It is, I fear, deficient in clearness, having deferred almost 

 to the last moment to prepare it ; and, moreover, being unable personally 

 to attend, to afford any required explanation. It is at least essential to 

 add, that the degrees are reckoned from the north point, round by the 

 eastern side, to the north again. 



