OBSERVATIONS OF WOLF’S, SWIFT'S, AND WINNECKE’S COMETS. 335 
RESULTS or OBSERVATIONS or WOLF’S COMET (II.) 
1891, SWIFT’S COMET (I.) 1892, anp WINNECKE’S 
PERIODICAL COMET, 1892, ar WINDSOR, 
NEW SOUTH WALKS. 
By Joun TEBBUTT, F.R.A.S. &. 
[Read before the Royal Society of N.S. Wales, December 7, 1892. ] 
Wolf’s Comet (II.) 1891. 
THis comet was first detected by Herr Max Wolf at Heidelberg, 
Germany, on September 17, 1884, and it was soon found that no 
parabola would satisfy its movements. Elliptic elements were 
accordingly calculated by several astronomers which gave a period 
of rather more than six and ahalf years. It passed its perihelion 
on November 18, 1884. The Astronomische Nachrichten, Vol. 
exvil, Nos. 2789 and 2790, contains a definitive investigation of 
the elements by Pfarrar A. Thraen from a fine series of observa- 
tions extending from September 20, 1884, to April 6 1885. The 
resulting period is 2474:5 days, and the return to perihelion was 
fixed for August 28, 1891. Approximate ephemerides were 
published for this return, which enabled Spitaler of Vienna and 
Barnard of Mount Hamilton to detect the comet on May 1 and 2, 
1892 respectively. It was subsequently followed at several 
morthern observatories. With the help of Thraen’s ephemeris in 
Astronomische Nachrichten, No. 3054, I found the comet on Octo- 
ber 9 with the four anda half inch equatorial. From that date to 
December 26 it was well observed at Windsor with a square bar- 
micrometer on the eight inch equatorial and in a dark field. The 
accompanying table gives the deduced apparent positions and 
the necessary reductions to the earth’s centre, these reductions 
being based on an equatorial horizontal parallax of the sun= 
8°85" and Thraen’s values of log. A in his ephemerides in Nos. 
3054, 3064 of the Astronomische Nachrichten. 
