638 PHILOSOPHICAL TRANSACTIONS. [aNNO 1683. 



cause their latitudes alter slowly, we may hence conclude the difference 8' 25" to 

 have been nearly their distance at that time, these tables being grounded on the 

 Tychonic observations made within less than 40 years after ; and showing the 

 latitudes of the planets well at this time, near 100 years later, we may conclude 

 to have answered them as well then ; and, if we consider how small a space the 

 distance of 8^ minutes appear to the naked eye in the heavens, especially be- 

 tween two such bright planets as Saturn and Jupiter, that the Caroline distance 

 agrees very well with the words of Junctinus, and that Riccioli was mistaken. 



Their next conjunction, according to Maginus's ephemerides, founded on the 

 Prutenic numbers, was April 29, 1583, in 21° of )^, the sun being then in 17° 

 of y ; so that the planets rising before him, in signs of short ascension and with 

 south latitude, this congress could not be observed by Tycho, who was mind- 

 ful of it, as appears by this note in page 55 of his Historia Ccelestis. May 30, 

 A. M. as soon as we saw Saturn after the conjunction, the following distances 

 between Jupiter and Saturn were taken with a radius, viz. at ih. 47 m. 3° 24'; 

 and at ih. 50 m. 3° 24'. 



The same ephemerides show the next conjunction of Saturn and Jupiter 

 1603, Dec. 14, at noon, in 9° 36' of I ; but the ingenious Kepler and our Sir 

 Christopher Heydon found it by observation 7 days sooner, or the 7 th day of 

 the same month in the morning, in near 8° of I ; the planets being then but 

 newly emerged from the sun's rays. 



The ephemerides of the learned Kepler, calculated from his own Rudolphine 

 tables, makes the next conjunction l623, between the 7th and 8th of July, in 

 6° 46' of ^ ; the planet Saturn being then only 4' to the north of Jupiter : but 

 this first conjunction in the fiery Trigon, happening under the sun's beams, was 

 not observable. 



By the same tables and ephemerides of Eichstade, calculated from them, these 

 planets met again in the 25th degree of X, between the 15th and l6th of Feb. 

 1643, with a degree difference of latitude. 



By the joint consent of Eichstade's and our Wing's ephemerides, the same 

 planets were in conjunction again l663, on the 10th of October at noon, in 

 13° 30' of I , with 1° difl?'erence of latitude. This conjunction was observable 

 after sun-set in our latitude, but I hear not that any one observed it. 



In each of these years there happened only one conjunction of the two 

 superiors: nor is it possible that there can be more, except the Heliocentric 

 conjunction fall near the opposition of the sun; for then there may be three, 

 two direct, and one retrograde, as has been within the space of 7 months, be- 

 tween October and May last inclusive, of which the true times are determined 



