642 PHILOSOPHICAL TRANSACTIONS. [aNNO 1683, 



Whence I collect the true places at this time, viz. 

 Of Saturn, Leo l6° 57' 10"; latitude 1° 13' 10'' 

 Of Jupiter, Leo 17 7 10 ; latitude 1 1 30 

 Differences of longitude, 10 O ; of lat. 11 40 



The retrograde motion of Jupiter from Saturn in 4 days, between the 26th 

 and 30th of this month, by my correct ephemeris, is 12' \5". I say therefore, 

 as 12' 15''' is to 4 days or 96 hours; so is lo' O", the difference of the planets* 

 present longitudes, to 78 hours, or 3 days 6 hours, wliich therefore added to 

 the time of that observation, Jan. 26 d Qhf, gives the true time of the con- 

 junction, Jan. 29, 16 hours after noon, or according to the common account 

 Jan. 30, at 4 o'clock in the morning. At which time both the planets are in 

 $1 l6°41-f', with 114- min. difference of latitude or distance from each other. 

 Which is further confirmed by the measured distances of the planets on the 

 30th at night before recited. 



On the 26th day, at gh. 40m., the sun*s true place was by my tables in ;x:f 

 17° 214-'; so that he was now about -^ of a degree past their opposition. 



Towards the latter end of the following April, the planet Jupiter began to ap- 

 proach Saturn again, both being now direct; the 28th at night, with the 16- 

 foot glass and micrometer, I measured the distances as below : 



April 28, 10^ 21"^ ... . between their centres ° 32' 35^ 



23 .... repeated 32 33 



24 .... between their next limbs 32 4 



26 .... repeated 32 2 



May 7, 8 59 ... . Jupiter from the Lion's heart .10 59 o 



9 1 ....repeated 10 59 o 



34- ... . Saturn from the Lion's heart 10 58 50 



5 ....repeated 10 58 50 



11.... Jupiter from E in the Lion's head 8 55 35 



15 .... repeated 8 55 40 



17 .... Saturn from the same star 8 39 40 



18 .... repeated 8 39 40 



With the Micrometer. 



30 .... between their centres 15 33 



33 ....repeated 15 37 



35 .... between their next limbs 15 3 



36 .... repeated 15 o 



40 .... between their remote limbs ]6 2 



42 ....repeated 15 58 



