Astronomical and Nautical Collections. 133 



Mean Time. 



March 28, 1822, ^ 7 magnitude Tauri immers. fi 54 30.2 



;• 30 !^.6 supposed yGemi 9 19 28.5 



April 1 6 Cancri .... 8 58 21.8 



C immers. 18 35 47,4 



10 Antares •? 



(. emersio 19 14 27.9 



Siidereal Tinw. 



July 11 5.6 Pise. . immers. 2 1 0.4 



From the occult, of Antares I find the mean time at Paramatta 



of true conjunction, — 



Perimm. 17 29 8.8 —5.54 rfL +5.89 dS -0.56 cZtt 



emer. . . . 19.82 + 2.44 . . —3.17 . —2.06 



From the Nautical Almanac follows the mean time of d in 



Green. 7 25 12.5. Hence long of Par. 10'' 4' 1".8 ; this may, 



however, be corrected by the Green. Lunar Obs. on that day. 



303 



I assumed for ratio of earth's axes. 



304 



Opposition of Mars, February, 1822. 

 These observations are a mean of several observations about 

 the meridian, each being singly reduced to the time of culmina- 

 tion. I made the observations with a repeating micrometer, ap- 

 plied to a telescope on an equatorial stand, and did not extend 

 them beyond 15' on each side of the meridian. 



Feb. 15 Mars less AR > J'^:lToo nr tvt r ■ ^, ^'^",?\ 

 than i Leonis \ ^ ^^ '^^ ^^^'^ ^.oUSl 2' 35".15 



16 Mars more AR? 6. 05 Mars South of > „ 

 than446 Mayer S 446 M. . \ 



On the 15th of February, at the time of culmination, Mars 

 was therefore 2' 35."15 north of i Leonis and on the 16th, when 

 on the meridian 0' 34. "84 south of 446 Mayer, which latter 

 star it must have eclipsed little after passing the meridian ; 

 clouds prevented me from seeing it : thence the parallax of Mars 

 might be inferred. 



Comet of Encke. 

 I did not see this comet before the second of June, 1822. I 

 send you here my observations thereof, which I believe to be so 

 correct as the position of the stars which I used for comparison, 

 taken partly from Piazzi, but chiefly reduced from La Lande 

 Histoire Celeste. ' 



K2 



