Mabch 2, 1883.] 



• KNOWLEDGE • 



127 



THE GREAT COMET OF 1882.— I.* 

 By Professor C. A. Youxc. 



THE comet which is fading in the morning sky is one 

 of the most interesting that has ever appeared. 

 Few, if any, have ever been more brilliant, and though 

 others have been larger, and have continued visilile for a 

 longer time, none of them have presented more remark- 

 able phenomena. 



Of late we have been much favoured in the matter of 

 bright comets. According to the list given by Humboldt in 

 his "Cosmos," it appears tliat the average interval between 

 such apparitions for the last five centuries has been some- 

 thing like eight years. During the last fifty years the 

 frequency has been about the same, conspicuous comets 

 having appeared in 1835, 1843, 1858, 1861, 1862, and 1874. 

 But since the beginning of 1880 we have already had five 

 which were visible to the naked eye, and three of them 

 comets of the highest rank. The comet of 1880 was 

 indeed visible only in the southern hemisphere : but we all 

 remember the fine comet which appeared in June, 1881, 

 and was not much, if at all, inferior to the present one. 

 Schaberle's comet, which followed in August, would have 

 been regarded as very satisfactory had its predecessor been 

 less brilliant : and Wells's comet of last summer, though 

 not well seen in the United States, was a very respectable 

 comet in South Africa. 



It is not yet certain when or where the present comet 

 was first seen, but, so far as now appears, the priority 

 belongs to Dr. Gould, or one of his assistants, at the 

 observatory of Cordoba, in South America. In a private 

 letter to Mr. Chandler, of Cambridge, mainly occupied 

 with other matters, Dr. Could, under date of Septem- 

 ber 15th, mentions that a brilliant comet had been visible 

 there near the celestial equator for "more than a 

 week." He had already made two observations, and was 

 waiting for clear weather again in hopes of being able to 

 catch it on the meridian. This would put its discovery on 

 or before Sept 7. It was seen on the 8th by 3Ir. Finlay, 

 an assistant in the Royal Observatory at the Cape of Good 

 Hope ; and on the 12 th it was observed at Rio Janeiro by 

 Cruls, who telegraphed the news to Europe, announcing it 

 (erroneously) as the expected comet of 1812 on its return. 

 We have not yet sufficiently full accounts from the 

 southern observatories to know whether it was lost sight 

 of at all after its discovery, but we have the account of a 

 most interesting and unprecedented observation made at 

 the Cape Town Observatory on the 17th. !Mr. Gill, the 

 director of the Observatory, writes : — " The comet was 

 followed by two observers with separate instruments 

 right up to the sun's limb, where it suddenly disappeared 

 at 4 h. 50 m. 58 s. local mean time." This was about an 

 hour and a half before its perihelion passage. 



A few hours previously it had been independently dis- 

 covered by Mr. Common, in England, in the full blaze of 

 sunlight, and clouds alone prevented liim from making the 

 same observation as Mr. Gill. 



It is evident that the comet must have been most in- 

 tensely brilliant to be visible 'under such circumstances. 

 When it passed on to the sun's disc (it was between us and 

 the sun at the time), it disappeared, being either trans- 

 parent, or else practically as bright as a portion of the sun's 

 own surface. If this comet had been in the place of the 

 little " Tewfik " which was seen close to the sun at the 

 time of the Egyptian eclipse last May, it would have been 

 something to remember. 



* From the Popular Science Monthly. 



On Sept 18 the comet had reached a greater distance 

 from the sun (about S'", and had become so conspicuous 

 tliat it was simultaneously rediscovered by a multitude of 

 observers in all parts of the world, and accurate determina- 

 tions of its position were made at several observatoriee. 

 On the ne.xt day every one had heard of it, and people 

 interested in astronomy thought and talked of nothing 

 else. 



On the 19th and 20th the comet was gtill easily seen by 

 the naked eye. On the 21st it was visible only in places 

 when the air was very clear and the sky darkly blue. On 

 the 22nd a curious observation of it was made at Paris 

 by M. Mallet who, at the request of M. de Fonviellc, 

 ascended for the purpose in a balloon provided by the 

 latter, thus getting above the clouds with which the city 

 was thickly covered. Of course, it was not possible in this 

 manner to make any precise deti rniination of position, 

 but the aeronaut obtained a fine view of the celestial 

 Wsitor. 



For a few days after this the comet does not appear to 

 have been observed until it had receded far enough from 

 the sun to become visible before sunrise. Then, for 

 awhile, during the early days of Octoljcr. it was a most 

 magnificent object, with a head at first rivalling Jupiter in 

 brightness, and a tail which, though not of unusual dimen 

 sions, never much exceeding 60,000,000 miles, was remark 

 ably well defined, dense, and luminous. It moved slowly 

 toward the south and west, and when, once in a while, a 

 clear morning permitted the view, it was seen to b«^ 

 growing fainter and more diffuse, though not smaller. 



To the naked eye or opera-glass it has, perhaps, pre- 

 sented fewer phenomena of interest than some other 

 comets — that of 1858, for instance. It has not exhibited 

 any of the peculiar secondary tails or straight streamers 

 which were so characteristic of that comet, nor has the 

 striation of the tail been marked, though evident enough 

 on close inspection. 



From Sept 27 to Oct 1, however, the tail was " rifted." 

 There was one obscure streak extending from the nucleus 

 through its whole length, described both by Ricco, of 

 Palermo, and Dr. Hastings, of Baltimore, and the latter 

 mentions another fainter one parallel to the first, and 

 shorter. 



On Oct 2nd the tail, as seen at Princeton, was about 

 14° long, exceedingly bright and sharp in its outlines, 

 slightly curved and convex to the horizon. It was 

 especially well defined near the head, and almost equally 

 so on both sides. On the 4th the upper edge was veiled 

 and rendered indefinite by a faint nebulosity which appeared 

 to have emanated from the head. Ricco's drawing of it, 

 as seen at this date in the clear Italian sky, shows some- 

 thing resembling a bright comet enveloped in a fainter 

 one ; but the smaller one is eccentric, and soutli of tike 

 middle of the hazy envelope. 



On the 1 0th, this external nebulosity had considerably 

 increased. Professor Smith, of Kansas University, noticed 

 on the 9th a pale stream of light with parallel edges, and 

 nearly as wide as the tail of the comet, extending toward 

 the sun. On the 15th, the phenomenon had become much 

 more conspicuous. The streamer was now over half a degro; 

 in width, well defined at both edges, of nearly uniform 

 brightness throughout, though nowhere as bright as even 

 the faintest portions of the tail, and extended from its 

 origin, a degree or two above the nucleus, to a distance of 

 two or three degrees below the head, where it faded 

 out The dotted lines in Fig. 1 (see next page) indicate 

 its form and dimensions. 



This streamer, which remained visible only a few days, 

 may have originated in the enveloping comet of Ricoo'B 



