Notices respecting New Booh. 299 



so much dilated as to more than fill the field of view in length, and 

 nearly so in breadth, of the great reflector. Every trace of coma 

 had disappeared. " The clear parabolic outline of the head was seen 

 free from any mistiness or vaporous appearance, in its full beauty ; 

 and certainly a more delicately formed and soft, yet well-defined, 



outline than it presented on this night could not be imagined 



All idea of vagueness or confusion connected with an ill-defined and 

 fluctuating coma being now absent, an impression of regularity of 

 structure, and of precise and definite laws obeyed in its constitution, 

 was no less strongly conveyed by this view of it, than by that of the 

 body of Jupiter or Saturn. From this time may be dated the com- 

 mencement of the development of the true tail The coma from 



this time appeared no more, but in the progress of the comet towards 

 its final extinction the semblance of a new coma arose from the dila- 

 tation of the mass of internal light immediately surrounding the 

 nucleus, after the final dissipation of the envelope, and which, from 

 being at first a subordinate and inconspicuous part of the phseno- 

 menon, became by degrees a leading feature, and at last may be said 

 to have constituted the whole visible comet, the infinitely minute 

 and hardly perceptible nucleus excepted." — 'P. 401. 



With respect to the small density of the comet, as indicated by 

 its almost inappreciable effect in extinguishing the light of small stars 

 seen through it, we have the following remark : — " I may here men- 

 tion, once for all, that among the innumerable stars of all magnitudes, 

 from the ninth downwards, which at various times were seen through 

 it, and some extremely near to the nucleus (though none exactly on 

 it), there never appeared the least ground for presuming any extinc- 

 tion of their light in traversing it. Very minute stars, indeed, 

 on entering its brighter portions, were obliterated, as they would 

 have been by an equal illumination of the field of view ; but stars 

 which before their entry appeared bright enough to bear that illumi- 

 nation, were in no case, so far as I could judge, affected to a greater 

 extent than they would have been by so much lamp-light artificially 

 introduced." 



From the 1st to the 11th of February the observations with the 

 reflector were suspended by reason of the moon approaching and 

 passing the place of the comet. On the latter day the comet was a 

 superb object, but grown much too great for the grasp of the tele- 

 scope with its ordinary sweeping power. The nucleus was then the 

 most conspicuous part. On the 17th it was " dilated to a vast size 

 and no longer sharply defined, but yet the outline well made out, 

 the nucleus pretty sharp, all but stellar, and much brighter than ever 

 seen before, but the interior cometic tail hardly perceptibly brighter 

 than the general tail. On the 19th the nucleus and its coma very 

 bright and highly condensed. The parabolic envelope hardly to be 



made out, and evidently distorted From this time forward the 



envelope continued still to dilate, being, however, worse defined and 

 fainter, till at length, on the 18th of March, all trace of a visible out- 

 line had disappeared." — P. 402. 



The last recorded observation of the comet was made on the 5th 



X2 



