658 PHILOSOPHICAL TRANSACTIONS. [aNNO I67I. 



viz. Saturn occulted by the moon; a lunar eclipse; occultation of Jupiter's first 

 satellite ; and the phases of Saturn and his ring. Of each of these in their 

 order. 



1 . Saturn occulted hy the moon. — Beginning of the occultation at Dantzick, 

 June 1, (new stile) 1671, was at 3h. 38m. 27s. in the morning, near the moun- 

 tain Germanicianus. The line of transit, as far as could be collected from the 

 ingress alone, was through mount ^tna, near the moon's centre; then by 

 mount Herminium, mount Hercules, and the upper part of Mare Caspium. 

 Excepting this year's observation, within 4 1 years, as far as I remember, I have 

 seen Saturn only two times covered by the moon; first, in the year 1630, Jan, 

 29, at llh. at night, when I was at the island Huanna in the Danish sea; and 

 again in the year 1661, Aug. 3, at 7h, 58m. 20s. in the evening, here at 

 Dantzick. 



2. A total eclipse of the moon, An. 1671. — This lunar eclipse was observed by 

 Hevelius at Dantzick, Sept. 1 8, new stile, in the evening. He was prevented 

 from seeing the beginning and most part of the eclipse, by rain the whole day ; 

 till 8h. 30m. after noon, when, through an opening in the thick clouds, he per- 

 ceived the moon rather obscurely, but so much enlightened, that the eclipse 

 seemed to have been quite over, at least that the interval of total eclipse was 

 past, and the moon recovering her light again ; so that he concluded the eclipse 

 must have happened above half an hour sooner than Kepler's calculation made 

 it. At 8h. 34m. he observed the moon had got out of the shadow a whole digit 

 at least, and again, at Qh. 41m. the moon's light had increased to 1-^ digit, as 

 near as could be judged. 



3. Occultation of Jupiter s first satellite hy his shadow. — ^This was observed by 

 Hevelius at Dantzick, 167I5 Sept. 7, new stile, in the morning. It had been 

 agreed on, by M. Cassini at Paris, and M. Picard at Uraniburg, to observe this 

 occultation of Jupiter's first satellite; and therefore, says Hevelius, I also 

 thought proper to attend to the same phenomenon. Hence, as soon as Jupiter 

 appeared at 4h. 27m. I found that all his four satellites were visible also, three 

 on the left hand and one on the right, as seen through my tube, which shows 

 objects in an inverted order. The two which were nearest him on the left 

 seemed to be not far from his limb, as also that on the right, which was the 

 least of them all. At 5h. 12m. beyond my expectation, the nearest satellite on 

 the left hand seemed entirely to vanish ; the three others remaining, though 

 that on the right hand also seemed to approach nearer and nearer to Jupiter. 

 Whether, indeed, that was the very moment of the immersion of the former 

 satellite I dare not certainly affirm, at least however that occultation did not 



