194 COSMOS. 



19th of December, 1845, already remarked a kind of pro- 

 tuberance toward the north ; but on the 21st there was, ac- 

 cording to Encke's observation in Berlin, still no signs of a 

 separation visible. The subsequent separation was first de- 

 tected in North America on the 29th of December, 1845; 

 in Europe, not until the middle and end of January, 1846. 

 The new smaller comet proceeded toward the north. The 

 distance of the two was at first 3', afterward (February 20th), 

 according to Otto Struve's interesting drawing, 6'.* The 

 luminous intensity varied in such a manner that the gradu- 

 ally increasing secondary comet for some time exceeded the 

 principal comet in brightness. The nebulous envelopes which 

 surrounded each of the nuclei had no definite outlines : that 

 of the larger comet, indeed, showed a less luminous protuber- 

 ance toward S.S.W. ; but the space between the two comets 

 was seen at Pulkowa quite free from nebulous matter. f A 

 few days later, Lieutenant Maury, in Washington, remarked, 

 with a nine-inch Munich refractor, rays which proceeded from 

 the larger older comet to the smaller new one, so that a kind 

 of bridge-like connection was produced for some time. On 

 the 24th of March, the smaller comet was scarcely percepti- 

 ble, on account of the decreasing luminous intensity. The 

 larger one only was seen up to the 16th or 20th of April, 

 when this also disappeared. I have described the wonderful 

 phenomenon in detail, $ so far as it could be observed. Un- 

 fortunately, the actual separation and the immediately previ- 

 ous condition of the older comet escaped observation. Did 

 the separated comet become invisible only on account of dis- 

 tance and feeble luminosity, or did it resolve itself? "Will it 

 be again detected as an attendant, and will the Comet of 

 Biela present similar anomalies at other reappearances ? 



The formation of a new planetary body by separation nat- 

 urally excites the question whether, in the innumerable com- 

 ets revolving round the Sun, several have not originated by 

 a similar process, or do not daily originate so ? whether they 



* The subsequent (5th of March) increase of distance seen to the ex- 

 tent of 9 19' was, as Plantamour has shown, merely apparent, and de- 

 pendent upon the approximation to the Earth. Both parts of the double 

 comet remained at the same distance from each other from February 

 until the lOrh of March. 



t " Le 19 Fevrier, 1846, on aper^oit le fond noir du ciel qui separe les 

 deux cometes." Otto Strnve, in the Bulletin Physico-math^malique de 

 I'Acad. des Sciences de St. Ptfeshourg, torn, vi.. No. 4. 



\ Compare Outlines,^ 580-583; Galle, in Olbers's Cometenbahnen, 

 p. 232. 



