12 Observations on Donati's Comet. 



divided light in front, and the sides of the nucleus, are less 

 distinct, while the usually darker part, behind the nucleus, 

 is now almost as luminous as those in front ; the whole tail is 

 nearly equally lighted, but the light is a little stronger near 

 the nucleus, and a little less so towards and at the end of 

 tail ; there is a faint increase of light at the margins of the 

 lower part of it. 



Fig. VII.— (Oct. 15.) 



[Sky, cirro stratus and cum. stratus (amount 6) ; wind, N.E., fresh breeze ; 

 barometer, 29"64; thermometer, 74"7 ; electricity, +1"75.] 



First appearance at 6h. 48m. p.m. ; altitude, 27°38'; no pul- 

 sation of light visible ; scarcely any difference in form and 

 light from Fig. VI. ; apparent diameter of nucleus equal 

 to Mars ; greatest brightness at about 7h. 48m. ; an extension 

 of light towards the sun again visible ; a small but sharp- 

 edged cloud-covered nucleus and part of tail at 7h. 25m. ; 

 through this cloud the light of the head of Comet was visi- 

 ble, but dimmed down to the degree of light in that part ol 

 tail which touches the cloud ; of the part of tail covered by 

 the cloud nothing is visible. 



Fig. VIII.— (Oct. 17.) 



[Sky, perfectly clear ; wind, S.E., light ; barometer, 29'91 ; thermometer, 

 54-3; electricity, +7 "74.] 



No pulsation of light. No remarkable change in the 

 general appearance of the Comet has taken place, it is very 

 much the same as on the 15th, with the exception that the nu- 

 cleus is rather smaller, brighter, and nearly round; a telescopic 

 star, near the nucleus and inside the tail, is quite bright and 

 clear ; greatest brightness of Comet about 7h. 48m. p.m. ; 

 again a brush of light extended towards the sun ; a star of the 

 fifth (?) magnitude in front of head, and another of the same 

 size on the end of tail. At 8h. p.m. the Comet stood not 

 far to the right of Antares, Venus still close to him, as repre- 

 sented in Fig. VIII. 



Fig. IX.— (Oct. 24.) 



[Sky, cirro cum. (8) cirro strat. (4) ; wind, N.E., strong breeze ; barometer, 

 29-94; thermometer, 71 "2; electricity, + 2' 17.1 



Time when the drawing was made : 7h. 40m. p.m. Although 

 seven days have elapsed since my last observation of the 



