216 ASTRONOMY. 



Comet of 1861. — The orbit of the great comet of 1861 has been thor- 

 oughly investigated by Herr Kreutz of Bonn, from 1,150 observations, 

 which extend over nearly a year. During this period the comet trav- 

 ersed an arc of 155^ of its orbit. Dr. Seeling had previously published 

 an orbit (an ellipse of four hundred and nineteen years), with which 

 the observations were compared. Thirty-one normal places (1861, May 

 28; 1862, April 23) were formed. Planetary perturbations were com- 

 puted for the whole interval, and the efiects of Venus, Earth, Jupiter, 

 and Saturn were alone sensible. The perihelion passage was, 1861, 

 June, 11.54 Berlin mean time, and the period comes out 409.40 ± 0.37 

 years. 



The small probable error of the period is noteworthy. Herr Kreutz 

 is continuing his researches on this comet. 



Faye's Periodic Comet — The British Eoyal Astronomical Society, at 

 its recent annual meeting, presented its gold medal to Prof. Axel 

 JVloller, director of the Observatory at Lund, in Sweden, for his investi- 

 gations on the motion of Faye's comet. Professor Moller's researches 

 commenced in 1860, soon after attention had been directed to this 

 comet by the offer of a prize for the accurate determination of its orbit 

 by the Society of Natural Sciences of Dantzic, and they have been con- 

 tinued to the present time, the comet's track at each of the three subse- 

 quent returns in 1865-'66, 1873, and 1880-'81 having been predicted 

 with a precision which has excited in no small degree the admiration of 

 astronomers; indeed, at the reappearance in 1873, M. Stephan's first 

 observation at the Observatory of Marseilles showed that the error of 

 predicted place was less than six seconds of arc, and after the last 

 revolution, when the perturbations from the action of the planets were 

 greater than in any previous revolution since the comet was first 

 detected by M. Faye, in 1843, the agreement between observation and 

 calculation was still very close. One important result of these investi- 

 gations has been a striking confirmation, from the motion of Faye's 

 comet, of the value for the mass of Jupiter deduced, by Bessel, from the 

 elongations of the satellites, the two values according within the limits 

 of their probable errors. 



In January, 1881, Mr. H. H. Warner, of Eochester, N. Y., founder of 

 the Warner Observatory, announced a prize of $200 in gold to any 

 American or Canadian who, during the year, should discover a telescopic 

 unexpected comet. When comet B, or the great comet, was discovered, 

 eflbrt was made to ascertain who first saw it, and had a conclusion been 

 possible among the thousands of claimants, a special prize would have 

 been given. As none could be reached, Mr. Warner determined to give 

 a special prize of $200 for the best essay on "Comets, their Composi- 

 tion, Purpose, and Eftect on the Earth.'- One hundred and twenty-five 

 essays were sent in to Director Swift, of the Warner Observatory, and 

 after a careful review, the judges — Prof. Elias Colbert of Chicago, 111., 

 Prof. H. A. Xewton of Yale College, New Haven, Conn., and Prof. H. 



