COMET (BIELA'S). 



113 



earnest in the support of the Union, was one 

 of the founders and an active member of the 

 Union League of Philadelphia, and by purse, 

 psn, and .voice, sought to further its work. 

 He was also an associate of the Sanitary Com- 

 mission, and did good service in caring for the 

 soldiers. After the war, he was appointed by 

 the Government one of the commissioners to 

 examine the whole internal revenue system, 

 and suggest such modifications as might light- 

 en its burdens and increase its efficiency, and 

 to this work he devoted much time and labor. 

 He was connected with most of the prominent 

 literary, scientific, and benevolent institutions 

 of Philadelphia, and was a liberal giver to all 

 objects of benevolence. He had accumulated 

 a large and very valuable library, which was 

 especially full on political and social science, 

 and this he bequeathed to the University of 

 Pennsylvania, with an endowment for a pro- 

 fessorship of Social Science. 



COMET (BIELA'S). About the close of 

 1872 news was received in England of the re- 

 discovery of Biela's comet by Mr. Poyson, the 

 government astronomer at Madras. This com- 

 et, which has a period of about six and three- 

 quarter years, had not been previously seen 

 since 1852. At that time it appeared in the 

 form of two distinct comets, as also it did on 

 the occasion of its return in 1846, before which 

 time it was a well-defined single object. In 

 1859 Biela's comet was invisible supposed to 

 be lost to observation in the sun's light. It 

 was not found in 1866, and then the impres- 

 sion obtained that in some way it had been 

 dissipated or destroyed. Subsequently, the 

 distinguished astronomer M. Schiaparelli ad- 

 vanced and ably sustained the theory that 

 meteoric showers are phenomena caused 

 by the passage of the earth through cometic 

 matter. This theory, generally accepted by 

 physicists, is now confirmed in the most strik- 

 ing manner, as follows: Calculations showed 

 that Biela's comet, if in existence, would cross 

 the orbit of the earth November 27, 1872. 

 On that particular day occurred a great star- 

 shower, especially visible over a large part of 

 England. The champions of M. Schiaparelli's 

 theory ascribed the magnificent meteoric dis- 

 play to the fact that the earth on November 

 27th had actually passed through the tail of 

 Biela's comet. At a meeting of the Eoyal As- 

 tronomical Society, Mr. Hind, superintendent of 

 the Nautical Almanac, pointed out how closely 

 the phenomenon of the shower accorded with 

 the theory. A Continental astronomer, M. 

 Klinkerfues, followed up the subject. It oc- 

 curred to him that since the earth had passed 

 through the train of the comet, the actual 

 track pursued by the comet was indicated; 

 and, after some calculations, he sent this 

 dispatch to Mr. Poyson at Madras: "Biela 

 touched earth on 27th ; search near Theta Cen- 

 tauri." In November and December that con- 

 stellation is not visible to advantage except in 

 the Southern Hemisphere. Mr, Poyson did as 



VOL. XII. 8 A 



requested, and, surely enough, in December he 

 found what appeared to be a comet in the re- 

 gion pointed out. It presented a circular as- 

 pect with a bright nucleus and a faint but dis- 

 tinct tail, about as long as a fourth part of the 

 moon's apparent diameter. At the date of our 

 advices Mr. Poyson had not rendered a full and 

 clear report of his observations ; but there was 

 no doubt that he found a comet on the track 

 where Biela's, as calculated, should have been. 

 Nothing is said of a companion comet (the 

 half of the original one) which was first seen 

 in 1846. This reported rediscovery of Biela's 

 comet confirms most remarkably the theo- 

 retical considerations by which the star-shower 

 of November 27th had been attributed to col- 

 lision with the comet's tail. The radiant point 

 of the shower was in Andromeda, and it had 

 been calculated that Biela's comet would over- 

 take the earth in that constellation. The fol- 

 lowing is from the pen of a well-informed 

 writer in the Corrihill Magazine, prepared be- 

 fore the news of Mr. Poyson's good luck had 

 reached England : 



It thus appears certain that the display of Novem- 

 ber 27th was a shower of Bielan meteors. But the 

 reader may desire to have some evidence showing 

 that this is not an after-thought, but in accordance 

 with ideas expressed before the display took place. 

 It may be well, therefore, to mention that, in the 

 Monthly Notices of the Astronomical Society pub- 

 lished on October 24, 1872, a month before the star- 

 shower, there appeared a list of 132 meteor-streams, 

 among which is one (No. 120), whose date is set at 

 November 30th by the Italian observers, Schiaparelli 

 and Zeziola, while our English meteor students set it 

 down for November 25th ; and not only is the radi- 

 ant of this shower set in Andromeda, but the remark 

 is appended that the shower is " supposed by D' Ar- 

 rest and Weiss to be connected with Biela's comet." 

 Then, in the same number, but in another article, 

 Prof. Herschel invites astronomers to be on the watch 

 for a display of Bielan meteors, mentioning that 

 " the date of the earth's passage through the comet's 

 orbit now falls in the end of November." 



But the actual appearance of the shower, so soon 

 after Biela's comet had passed, combined with the 

 perfect agreement between the movements of the 

 meteors and the position of the comet's p^ath, must 

 be regarded as rendering certain that which before 

 had been but highly probable. Those who wit- 

 nessed the display of November 27th may be per- 

 fectly assured that they were then watching the fall 

 of bodies associated with one of the most interest- 

 ing of all the comets ever studied by astronomers. 

 The collision so dreaded in 1832 was in 1872 act- 

 ually in progress ; the process of dissipation com- 

 menced in January, 1846, was illustrated and, per- 

 haps, carried^ to a further stage last November ; and, 

 lastly, the disappearance of Biela's comet becomes 

 explicable when we perceive of what slight materials 

 the comet's train is formed. During the five hours 

 of the display the earth tunnelled a path (as it were) 

 through this train a path a quarter of a million 

 miles long, and having a circular section nearly 

 8,000 miles in diameter ; and yet, in this enormous 

 tabular section of the train, having a volume of about 

 twelve millions of millions of cubic miles, there 

 were but some thousands of scattered shreds of mat- 

 ter, so minute as to be unable to penetrate our atmos- 

 phere. Melted and vaporized high in the more tenu- 

 ous regions of the atmosphere, these small bodies 

 doubtless sank in the form of an inpalpable powder 

 to the surface of the earth, occupying many days, 

 perhaps, in their descent. 



