Observations on Donati's Comet. 11 



nous matter, which is united with the former, and likewise 

 entered the tail. On the foremost point of this second band 

 of light is an extension of it towards the sun. Close to the 

 nucleus, away from the sun, is a dark space, of the length 

 of two or three apparent diameters of the nucleus, gradually- 

 diminishing in width and darkness as it recedes from the nu- 

 cleus. Upper contour of tail convex and longer than the 

 lower one, which is concave. The last third of the tail is 

 filled with light equally distributed throughout it. The 

 color of light in the tail and around the nucleus is of a some- 

 what whitish hue. 



Fig. V.— (Oct. 13.) 



[Sky, cirro stratus, veil on the sky ; wind, S.E., light; barometer, 29.91; 

 thermometer, 61 7; electricity, +5 - 35.] 



First appearance at 6h. 55m. p.m. ; altitude, 20° 3'. As 

 yesterday, the pulsation visible, ceasing after the Comet 

 reached its greatest brightness, which was about 7h. 42m. 

 The nucleus of to-day is smaller, more condensed, rounder, 

 and brighter ; the color like Venus. The band before the 

 nucleus has disappeared, and a strong, uniform light is all 

 round it. There is no extension of this light towards the sun, 

 as observed yesterday. The tail, near the nucleus, is com- 

 pletely filled with luminous matter for one-fourth of its 

 whole length; the rest of the tail is divided, showing, as 

 usual, a stronger light on the outer margins, especially 

 on the convex one, and leaving the middle part darker. 

 Misty air prevented further observations. 



Fig. VI.— (Oct. 14.) 



[Sky, perfectly clear ; wind, S. byE., very light ; barometer, 29 '94; ther- 

 mometer, 59-5; electricity, +6 '65.1 



First appearance to-day at 6h. 45m. p.m. ; altitude, 24°34\ 

 pulsation of light of short duration and very weak ; greatest 

 brightness at 7h. 45m. p.m (see Fig.) ; nucleus still 

 smaller, when compared with yesterday's. The lumi- 

 nosity round the nucleus more concentrated, more in- 

 tense, and better defined, with the exception of one part, 

 where, to-day, there is again visible an extension of light to- 

 wards the sun, as seen on the 12th ; the convexity of the 

 upper part of tail is to-day increased ; the two wings of 

 luminous matter, emanating from the accumulated and un- 



