COMETS. 



and on the oth of November, to 2. The comet was observed on 

 the day of its perihelion by M. Struve, at the Observatory of 

 Pultowa, when no tail whatever was apparent. 



The circumstances which accompanied the increase of the tail 

 from 2nd October, untjj its disappearance, were extremely remark- 

 able, and were observed with scrupulous precision, simultaneously 

 by Bessel at Kouigsburg, by Struve at Pultowa, and by Schwabe 

 at Dessau, all of whom made drawings from time to time, delineat- 

 ing the successive changes which it underwent. 



On the 2nd, the commencement of the formation of the tail took 

 place, by the appearance of a violent ejection of nebulous matter 

 from that part of the comet which was presented towards the sun. 

 This ejection was, however, neither uniform nor continuous. 

 Like the fiery matter issuing from the crater of a volcano, it was 

 thrown out at intervals. After the ejection, which was con- 

 spicuous, according to Bessel, on the 2nd, it ceased, and no efflux 

 was observed for several days. About the 8th, however, it re- 

 commenced more violently than before, and assumed a new form. 

 At this time Schwabe noticed an appearance which he denominates 

 a " second tail," presented in a direction opposed to that of the 

 original tail, and, therefore, towards the sun. This appearance 

 seems, however, to be regarded by Bessel merely as the renewed 

 ejection of nebulous matter which was afterwards turned back 

 from the sun, as smoke would be by a current of air blowing from 

 the sun in the direction of the original tail. 



From the 8th to the 22nd, 



Fig. 9. Sept. 29. 1835. .. 



the form, position, and bright- 

 ness of the nebulous emana- 

 tions underwent various and 

 irregular changes, the last 

 alternately increasing and de- 

 creasing. 



At one time two, at another 

 three, nebulous emanations 

 were observed to issue in 

 divergent directions. These 

 directions were continually 

 varying, as well as their com- 

 parative brightness. Some- 

 times they would assume a 

 swallow- tailed form, resem- 

 bling the flame issuing from 

 a fan gas-burner. The prin- 

 cipal jet or tail was also observed to oscillate on the one side 

 and the other of a line drawn from the sun through the centre 

 198 



