Observations on Donati's Comet. 13 



Comet, it seems to me as if no great change in its general 

 aspect has taken place. The following points, however, I 

 thought worth noticing : the whole Comet, of course, 

 smaller ; tail shorter, in proportion to the diameter of the 

 head (or the mass of light surrounding the nucleus) ; nucleus 

 smaller, but still well defined, showing, as from the beginning, 

 the same pale-yellowish color ; telescopic stars visible clearly- 

 through tail, which ends near a cluster of them in the milky 

 way ; the convexity of the upper margin is now changed for a 

 straight margin, and the lower margin, formerly concave, is 

 now convex ; that brush of light extends still from the top of 

 head towards the sun. 



Fig. X.— (Nov. 7.) 



[Sky, cum. strata (amount 5); wind, S.E., light breeze ; barometer, 29 93; 

 thermometer, 53°2 ; electricity, +l - 55.] 



Nucleus round, still very distinct and bright ; light in head 

 equally distributed, diminishing quickly as soon as it has 

 reached the tail ; tail swelling towards the middle, diminish- 

 ing towards the end to an indistinct point — resembling a 

 horse's switch tail — very faint in light ; a telescopic star, 

 close to nucleus, has its full light ; no brush of light on 

 front of head ; the drawing was made at 9h. 30m. p.m. 



Fig-. XI.— (Nov. 12.) 



[Sky, cirro cum. cirro strat. (amount 5) ; wind, SS.E., light; barometer, 

 29-81; thermometer, 58°6; electricity, +1-84.] 



Nucleus was still very distinct ; the luminous matter in head 

 and in part of tail nearest to nucleus, condensed ; remainder 

 of tail very dim and short, without the pointed end, as seen 

 in Fig. X. ; boundary lines of tail indistinct in shape ; no 

 light was seen extending towards the sun, coming from the 

 undefined globe of luminosity surrounding the nucleus ; time 

 of observation, 9h. p.m. 



This is the last drawing I made of Donati's Comet, when 

 it was already out of reach of the naked eye of man. 



I merely place before the Philosophical Institute simple 

 facts, leaving it to the more learned men here, and at home, 

 to draw their conclusions therefrom. I hope our clear atmos- 

 phere allowed me to make such drawings as will be found not 

 quite valueless for completing the series already begun by 

 other observers. 



Melbourne, November 1858. 



