ASTRONOMICAL PHENOMENA AND PROGRESS. 



39 



DISCOVERY AND ANNOUNCEMENT OF COMETS. 

 In a statement of work done at the Harvard 

 College Observatory during the years 1877- 

 1882, by the director, Professor Edward 0. 

 Pickering, the following account is given of 

 the methods adopted in the systematic search 

 for comets, the announcement of discoveries, 

 and the early determination of coinetary or- 

 bits: 



By securing the services of Mr. Chandler as an as- 

 sistant, and by the co-operation of Mr. Ritchie of the 

 " Science Observer," a scheme has been developed 

 which has made great advance in the early announce- 

 ment of comets. When a comet is discovered, notifi- 

 cation is usually sent to this observatory by telegraph. 

 If the discovery was made in this country, a telegram 

 is at once sent to the Dun Echt Observatory, and 

 thence distributed throughout Europe. The iollow- 

 ing evening, if clear, an observation of the comet is 

 taken, and the resulting position telegraphed to 

 Europe. These early positions have in some cases 

 proved of great value, and have been used again and 

 again in each subsequent orbit. Great care has been 

 taken to avoid all delay in sending them, with the re- 

 sult that occasionally these precise positions have be- 

 come known abroad before the discovery itself had 

 been announced by the usual method. As soon as 

 these observations are obtained, the computation of 

 the orbit is begun, and the work continued at all 

 hours of the day or night until the results have been 

 translated into the "Science Observer" cipher and 

 cabled. About four days after the comet is discov- 

 ered its elements and ephemeris are generally printed 

 and distributed in this country and in Europe. Bv 

 an arrangement with the Signal Service and with 

 other observatories, when cloudy weather is expected 

 here, observations are sometimes obtained elsewhere 

 to avoid delay. Such arrangements have been made 

 with the daily papers and with the Associated Press, 

 that any important observation made here before mid- 

 night would probably be printed in the papers of the 

 following morning in the principal cities of the coun- 

 try. 



By the same system of co-operation a plan for 

 sweeping for comets has been developed, in accord- 

 ance with which a number of observers have under- 

 taken to examine a certain portion of the heavens 

 once or twice every month, and satisfy themselves 

 that no comet within the reach of their telescope is to 

 be found there. The results published in the u Science 

 Observer" show that the entire heavens is now so 

 thoroughly swept that a comet is not likely to be long 

 visible without detection. 



The observers engaged in this systematic 

 search in the northern hemisphere are Mr. T. 

 S. H. Shearman, of Brantford, Canada ; Mr. E. 

 S. Martin, Wilmington, N. 0. ; Mr. A. S. Will- 

 iams, West Brighton, England; M. C. De- 

 taille, Paris, France; Dr. H. Oppenheim, Ber- 

 lin; Dr. Lewis Swift, Rochester, N. Y. ; Mr. 

 E. E. Barnard, Nashville, Tenn. ; Professor E. 

 L. Larkin, New Windsor, 111., and Mr. W. R. 

 Brooks, Phelps, N. Y. In the southern hemi- 

 sphere, Mr. John Tebbutt, of Windsor, N. S. 

 Wales, takes the zone between the 20th and 

 40th parallels of latitude ; Mr. A. B. Biggs, of 

 Launceston, Tasmania, from the 40th to the 

 60th ; and Mr. W. Bone, of Castlemaine, Vic- 

 toria, from the 60th to the 80th. 



METEORIC SHOWERS. The meteors of April 

 20th were more numerous than usual in 1882. 

 Mr. H. Corder, of England, watching from 

 9 h ' 30 m> to 12 h - 30 m> , counted thirty-four me- 



teors, of which twenty-six were conformable 

 to the radiant in Lyra. Mr. Corder, who has 

 given attention to the meteors of this stream 

 for the last six years, found the hourly num- 

 ber twice as great in 1882 as in any other year 

 since 1876. Four of the meteors were equal 

 to stars of the first magnitude. The radiant 

 point was near Theta Lyrse, in right ascension 

 268, and north declination 37. 



The meteors of the August shower were 

 much more numerous in some localities than 

 in others. In "Nature," for September 28th, 

 Mr. Donald Cameron, of Glasgow, Scotland, 

 gives the result of his observations from the 

 6th to the llth of August inclusive. The 

 showers witnessed on the nights of the 9th, 

 10th, and llth, are described as "gorgeous." 

 On the evening of the 10th, before the close of 

 twilight, he counted thirteen very large me- 

 teors in the space of a few minutes, although 

 his view was much intercepted by trees and 

 buildings. Mr. Cameron does not give the 

 whole number observed, but he remarks that 

 he had not for years during any month wit- 

 nessed so grand a display of meteors as in Au- 

 gust, 1882. The shower "was of very short 

 duration on each night, and after twelve 

 o'clock not one scarcely could be seen." 



According to the " Sidereal Messenger," for 

 October, 1882, watch was kept for the Au- 

 gust meteors at several points in Indiana on 

 the nights of the 8th, 9th, 10th, and llth. At 

 Bloomington, on the night of the 10th, a 

 party of four, under the direction of Professor 

 D. E. Hunter, counted 521 meteors in four 

 hours, commencing at 10 h- 30 m- . This was an 

 average of 130 per hour. Of these, 139 were 

 estimated as of the first magnitude, 99 of the 

 second, and 76 of the third. A stationary me- 

 teor was seen at l h- 34 m- , which increased from 

 the fourth to the first magnitude. This, of 

 course, was at the point of divergence, and 

 moving directly toward the observers. A 

 bluish Perseid of the first magnitude appeared 

 in Draco at l h- 33 m ', and moved in a track ap- 

 parently curved. In a second or two this was 

 succeeded by another, of nearly the same size 

 and color, which moved in precisely the same 

 path. The meteors frequently came in clus- 

 ters, five or six sometimes appearing in quick 

 succession. At other times a lull or total ces- 

 sation would last several minutes. 



In one hour from eight to nine on the 

 evening of the 10th, Mr. W. F. L. Sanders, 

 watching alone at Jasper, Dubois County, ob- 

 served forty meteors. 



At Bloomfield, Greene County, Ind., Dr. 

 H. R. Lowder and others kept a continuous 

 watch on four nights, commencing at nine 

 o'clock on the evening of the 8th. The ob- 

 servers counted 



On the night of the 8th 761 meteors. 



9th 1,527 



" " 10th . 3.677 " 



llth... . 667 



Total in four nights 



