xviii President's Address 



thought not improbable that the comet of 1812 would again 

 return to perihelion this year, and " searching ephemerides" 

 had actually been prepared and distributed by some French 

 astronomers (Paris Observatory), it was at first thought 

 possible this might be that comet, but an approximate orbit 

 computed by our vice-president, Mr. White, from some of the 

 earliest observations of the present comet, made any futher 

 supposition of this kind altogether untenable. The approxi- 

 mate elements exhibit a remarkable likeness to the great comets 

 of 1843 and 1880. The motions of all three are retrograde, 

 the inclination and longitude of the node very similar, and 

 the perihelion distance of all exceedingly small and nearly 

 like. 



The apparitions of two large comets in 1880 and 1882, with 

 elements so very much alike that of the grand comet of 

 1843, have of course led to some astronomical specula- 

 tion on the subject. If any celestial bodies appear suc- 

 cessively in similar or nearly similar orbits, a supposition 

 that they are one and the same body, or several separate 

 bodies in the same orbit, is quite reasonable. Mr. Tebbutt, 

 our well known astronomer, of Windsor, N.S.W., has 

 therefore suggested it as quite possible that the comets of 

 1843, 1880, and 1882 are identical, returning to perihelion 

 at rapidly diminishing periods, and that if this be so, its 

 present excursion must be very short, barely taking it out 

 of our sight before it turns back again towards the sun. One 

 incentive to this suggestion was no doubt the fact that the 

 perihelion distance of the rough orbit first computed was 

 less than that of 1880, while that of 1880 was less than that 

 of 1843. More recent calculations, however, show that the 

 perihelion distance of this comet was greater than at first 

 computed, and rather greater than that of 1880. Whether 

 we can possibly entertain this hypothesis will soon be shown 

 by the recession or return of the comet. If it disappear for 

 any considerable time, then we must conclude that there are 

 two or more comets in the same orbit. Numerous critical 

 examinations of the physical appearances of this body have 



