VOL. LXXX.] PHILOSOPHICAL TRANSACTIONS. (J2l 



which he supposed to be the 4th satellite going to emerge. At 23™, the black 

 spot had advanced a little towards the preceding side. At 30"^, it was still ad 

 vancing, and he saw that the spot was a little to the north of the equatorial belt, 

 but so that a small part of it was on the belt. At 35™, the black spot was a 

 little more than -i- of the diameter of Saturn advanced from the following edge 

 towards the centre. At SQ™, the satellite was detached. At 49™, the spot was 

 advanced so as to be about 4- of its way towards the centre ; and the 4th satellite 

 near half its own apparent diameter clear of the edge. 



In this situation of the planet Dr. H. took an eye-draught of it (fig. 10) as it 

 appeared with the black spot on the belt ; the lately emerged 4th satellite ; 2 

 parallel dark belts, the intermediate space between them and the equatorial one 

 being a little brighter than the rest of the disc ; the 6th, 3d, and 2d satellites on 

 the preceding side ; the ring projecting like 2 very slender lines on each side of 

 the disc, and containing the 1st satellite on the following arm, with the 5 th at a 

 considerable distance following. 



At O*^ 5^, the black spot was got a little more than half way towards the 

 centre. It was much darker than the belt, and more on it than before. At 

 1^ 2"^, by advancing gradually towards the south, it was now almost entirely 

 drawn on the equatorial belt. At 1^ 13"^, the black spot approached towards a 

 central situation. At 1^ 21^" 51% it was perfectly central, and at the same time 

 on the middle of the equatorial belt. He followed the shadow of the satellite 

 with great attention up to the centre, in order to secure a valuable epocha, 

 which may serve to improve our tables of the mean motion of this satellite. 



//. Astronomical Observations on the Planets Venus and Mars, made with a 

 View to determine the Heliocentric Longitude and uinnual Motion of the Nodes, 

 and the Greatest Inclination of their Orbits. By Thes. Bugge, F. R. S., 

 Regius Prof, of jlstronomy at Copenhagen, p. 21. 



1 . The heliocentric longitude and annual motion of Venus' s nodes. 

 The following astronomical observations were made at the Royal Observatory 

 at Copenhagen with a 6-feet transit instrument, and with a mural quadrant of 5- 

 feet radius. It is only necessary to set down the observed geocentric longitudes 

 and latitudes, corrected for aberration and nutation, and compared with the tables 

 of Dr. Halley and of M. de la Lande. 



