.VI CONTENTS. 



CHAPTER II. 



RECENT ADDITIONS TO OUR KNOWLEDGE OF COMETS. 

 SECTION I. 



PAQB 



THE GREAT COMET OP 1843, 121 



Seen at noon-day, 121 



Orbit of this Comet, 125 



Has this Comet been seen before ? .129 



SECTION H. 

 FATE'S COMET OF 1843, . . - 132 



SECTION III. 

 DE Yico's COMET OP 1841, . . 136 



SECTION IY. 



BIELA'S COMET 140 



Double appearance of this Comet in 1846, 141 



Relation of these two bodies, . . . . . . . 143 



Appearance of the Comet in 1852, ....... 144 



Cause of the separation, 146 



SECTION V. 

 Miss MITCHELL'S COMET, 150 



SECTION VI. 

 EXPECTED RETURN OP THE COMET OP 1264, . . . . 153 



SECTION VII. 

 THE GREAT COMET OP 1853, 15T 



CHAPTER III. 



ADDITIONS TO OUR KNOWLEDGE OF FIXED STARS AND 

 NEBULA. 



SECTION I. 



DETERMINATION OP PARALLAX OP FIXED STARS, .... 159 

 Bessel's determination of the parallax of 61 Cygni, . . . .161 



