VARIATIONS OP APPEARANCE. 



At 20 h 30 m s. t., the head presented the appearance represented 

 in fig. 17 (page 204). The chief coma was almost exactly cir- 

 cular, and had a diameter of 

 165". With a power of 198, 

 the nucleus appeared as in 

 the figure, the diameter being 

 about !" 25 to 1"-50. The 

 flame issuing from the nu- 

 cleus, curved back like smoke 

 before the wind, was very 

 conspicuous. The appearance 

 of the formation of the tail as 

 it issues from the nucleus was 

 remarkably developed. 



97. On the 5th of Novem- 

 ber the comet appeared as 

 shown in fig. 18 (page 204). 

 This drawing represents the 

 nucleus and flame issuing 

 from it on the scale of seconds 

 .given below. 



The proper nucleus was 

 found to measure about 2"-3. 

 Two flames were seen issuing 

 from it in nearly opposite 

 directions, and both curved 

 towards the same side. The 

 brighter flame, directed to- 

 wards the north, was marked 

 by strongly defined edges. 

 The other, directed towards 

 the south, was more feeble and ill-defined. 



10' 



20" 



GO'' 



180'' 



120" 



ILI1L 



I I I 



98. Sir J. Herschel, who also observed this comet himself at 

 the Cape of Good Hope, makes from all these observations the 

 following inferences. 



(1.) That the matter of the comet vaporised by the sun's heat 

 escapes in jets, throwing the comet into irregular motion by its 

 reaction, and thus changing its own direction of ejection. 



(2.) That this ejection takes place principally from the part 

 presented to the sun. 



(3.) That thus ejected it encounters a resistance from some 



203 



