52 PHILOSOPHICAL TRANSACTIONS. [aNNO iS/S. 



vations had a southern latitude in respect to the line of his wings ; but in the 

 first it was further distant from Saturn than in the second. 



We could not see Saturn again till the 23d of Dec. and then, in the presence 

 of Messrs. Huygens, Picard, Mariotte, Romer, and others of the Royal Aca- 

 demy of the Sciences, we found a small star westward of Saturn, between him 

 and his ordinary satellite, which was on the west also, almost at a double dis- 

 tance. And at that time we had no other reason to suppose it to be different 

 from the former, but that it had no latitude at all in respect of the line of Sa- 

 turn's wings. The weather did not suffer us to see Saturn again till the 30th of 

 Dec. and then we saw a little star on the east of him, without any latitude, 

 between him and his ordinary satellite, which had passed also to the east of him. 

 This observation, compared with the foregoing, kept us yet in suspense, because 

 we know not, whether this, which seemed to us the same with that of the fore- 

 going observation, had passed from one side of Saturn to the other, by only 

 one motion slower than that of the ordinary satellite, and consequently by a 

 little arch of a greater circle ; or whether, during this interval of time, it had 

 made one or more turns by a lesser circle ; which was Tnuch more agreeable to 

 the position in which it had appeared, without latitude, in both observations. 



The Heavens were not favourable to us again till the 10th of Jan. l673; and 

 then this little star appeared to have returned almost to the same position in 

 respect of Saturn, and his ordinary satellite where it had been Dec. 23. We 

 wondered to have found three times successively, this small star between Saturn 

 and his ordinary satellite, always nearly equally distant from them both. But 

 our admiration ceased at the 4th observation, made Jan. 15, in which the ordi- 

 nary satellite was to the east, and the new one west, as it had beefn in the fore- 

 going, but a little nearer to Saturn. We had that evening time enough atten- 

 tively to observe this planet for a whole hour together, during which we per- 

 ceived it approached to Saturn on the west, and consequently was in the supe- 

 rior part of its circle ; which fully confirmed us in the supposition that it was an 

 interior satellite. Thus the pursuit of another satellite, which we knew to be 

 further distant from Saturn, and to have a longer period, made us discover this 

 which is nearer to it, and whose period is shorter. 



Then it was, that comparing the observations together, we began to find the 

 nature of the motion of the new interior satellite. For the last two showed us, 

 that in 5 days it had made more than a whole revolution. The first observation 

 compared with the third, showed that in 1 8 days it had made a number of 

 revolutions, almost whole ones, which certainly were four; each of them of 4-i- 

 days: So that between the 10th and 15th it might be, that there had been one 

 revolution of 4-1- days, or two revolutions of 2i- days each. But the combination 



