VOL. VI.] PHILOSOnilCAL TRANSACTIONS, fiS^ 



happen later, although I grant that it might perhaps happen about a minute 



sooner. , 



The Observations. The Times corrected. 



Jupiter was first seen 4^ 32"^ 7* 



The altitude of the star Procyon 34° 43' 5 1 7 



The first of the satellites disappeared 5 12 



The altitude of Procyon 36 39 5 23 27 



4. Transit of the moon above Jupiter. — This he observed at Dantzick, An. 

 1671, Sept. 30, in the morning, new stile. In a very clear sky, with a tube of 

 20 feet, with great eagerness he observed the rising moon, and Jupiter a little 

 after. He found by his large brass octant, of near 9 feet radius, that Jupiter 

 was yet at 1° 23' 40'' distance from the eastern limb of the moon, and that all 

 his four satellites were seen towards the right hand, from whence the moon ap- 

 proached. An unfortunate accident prevented him from taking the very mo- 

 ment of conjunction. For when Jupiter now approached within 3' of the 

 moon's eastern limb, and was only 6' from the line of conjunction drawn 

 through both horns, some little clouds intervening prevented him from seeing 

 both Jupiter and the moon. The Rudolphine tables indicated an occultation, 

 and that much sooner than it could happen, yet there was none, but only a very 

 near approach, the moon being a little above Jupiter, by about 2 digits, the 

 time of which was 7h. 26m. 



5. The Appearance of Saturn and his ring. — According to the hvpothesis of 

 M. Huygens, Saturn was to resume his round figure in the summer of 1671, 

 the ring not appearing, being turned edgeways towards the earth. It was ob- 

 served by Hevelius and others. How it appeared, says he, Sept. 11, new stile, 

 I have delineated very truly and carefully, and have here sent you the scheme 

 (see fig. 12, pi. 14.) But in the months of June, July, and August, that vou 

 should see it quite round, as the Parisians affirm, I can hardly imagine. For 

 though the arms of Saturn might appear very close at the sides, even in a tube 

 of 60 or 70 feet, yet I can hardly think they could quite vanish, so that no re- 

 mains of them could be seen. Perhaps those gentlemen might view Saturn with 

 short telescopes during the twilight when the moon was up. 



Extract of a Letter from Dr. Fogelius, dated Hambtirg, Nov. 1, 

 1671, concerning the Spots of the Sun returned, and the last Eclipse 

 of the Moon. Observed hy Henry Sifer. Translated from the 

 Latin, N" 78, p. 3033. 



We found here^ as M. Hevelius had done at Dantzick, that the Rudolphine 



402 



