( + 1 ? )
likc »ppears yet More evidently m the Fourtb Satellite. By the Obfer-rations of Mr. Flamjleed at Grecnwich. An. i68x. Sept. 1\. 17h 45-'. 7 . App.but 17 h za.. T. Eq. thc Fourtb Satellite was leen newly come out of the Slra-dow, so that about 17h 30 7 . T. Eq. the first beginning of Emcrfion was conje-ctured • and aster 5 Revolutions, vi%. Dccemb. 17^ 1 ih 1 6' or 11 h 18'. T.F.q.hc again observcd the first Appearance of the Satellite beginning ro Emerge,that is,aster an Interval ofttjd 17^ 48'; whercas tliis Satellite mukcs fice meariRevolutions in 836 l 8h x^’.. Here we have 37'’. to be accounted for bythc severa! Inequalities. Ofthis i\' is due-to the first /Equations, which isrcduced to 19' by the Greater Continuance of the latter Eclipfc, Jupiter thenApproaching to his Descendhig Mode. So that there reinains onlv’ 1 S'i- for theDifference ot the id. ^Equations, whiist the Earth approachcd Jupiter , bymore than the Radius of its own Ofb : and the Difference of thc id. /F.qua-tions of the First Satellite , being according to Cafjini 8 7 30. the l.tid Distorence in the Fourtb otight to be 1 h ac/i, instead of i8i' ; whence the luter,valof thele two Emejions would be according ro his Prceepis, but 836 1 6h.
46^ instead of 8jd iy h 48' observed. And whereas 1 8';, may secm roo-»great a Difference; it must be norcd, first, that M. Rt-mer had stat cd thewhole id. jEquation 11' oo". which M: Cafflui has dimintshed to 14 7 1 est.
1b that instead of S'i.. M. Ferner allows 13^ and secnndly, that in the first of'thc se Observations, being about half an Hour before Sun rise, the Brightncssof thc Morning' might well hinderthe sceing of this (htallest and ilowcst Sa- ■tellite, till such timeas a good part thereof was Emergcd. -
XCIIL Havingagrcat Defirc to observe the Bddy of Mars, whiist Acror.y-atl and Retrograde ( having former!;/ with a Glats about Ix Foot long, ob- 14*™ about hi>ierv’d dorne kind of Spots in the Phase cf it) though it Was not in the Peri - ^v» t b Dr -hcliumof irsOrb, but nearer its Apbclium j yet 1 found that the Face of it, H " 00 g' ”• n 'when near its Opposition to thc Sun ( with a Charge, the 16 Fooc-Glals, l^z»,' " 14made use of, would well bcar ) appeared very near as big, as that of the Mounto the naked Eye.
But such had beer, the »11 I/stpofition of .the Air for severa 1 Nights, thatfrom more than ac Observations of it which I had. made linee its being Re-trograde, I cculd-sindnotbing of Satisfacfion, though l osten iniagincd, i sew-Spots, yet the Instcctive.Veins of the Air ( if I may lr* call thole paris, vvlfichbeing interlpcrs’d up and down in it, have a greater or lefs Rcfracstivc Power,than the Air next adjoining, with which they are mm ) clid make it lo con-fused andGlaring, that I could not eonclude upon any thing.
On the 3 d. of Mar. ch ^o 7 . in the. Morning' though the Air was stillbad enough, yet 1 could fte now and then the BodV of Mars, which I de-fcribed by the siebente H; as exactly represeiuing what I läw through thc t; *-Glase as I could.
An. I 66y. Mar. 10. O** icl. in the Moming findingthe Air very bad, I madeufe of a Very fhallow Eye-Glase, as finding nothing distinct with the greater-Charge, and law the-Appearance of it as in C, which 1 Imagined might be the- Kj. 147, .Rcpresentation of thc former -Spots by a leiser Charge. About ? of the Cloclc ■
the.