20 



was very thick and unfavourable for the week or ten days 

 after the tail was first seen. It happened, too, unfortunately 

 that I was all alone; the Assistant Astronomer, Mr. Ringwood, 

 being absent in Tasmania, and only returned on the morning' 

 of the l(Jth. On the five evenings on which I saw the nucleus 

 it was too faint to bear any illumination of the field, and in 

 taking the measurements I had to bring it to the edge of the 

 comb of a bifilar micrometer, iising a very low power ; the 

 observing-room was also kept dark. 



In the accompanying map (plate III.) I have laid down 

 approximately the path of the comet between the 2nd and 17th 

 of February, and the position of the tail amongst the stars. 

 The first thing that will strike you on looking at this diagram 

 will be the rapid extension of the tail, which, within a few 

 evenings from its first appearance, lengthened out from an 

 altitude of about 15 deg. or 20deg., up to within a short dis- 

 tance of the zenith. The rapid manner, too, in which it finally 

 faded away, leaving the small faint nebulous nucleus with 

 scarcely a trace of a tail after the 14th, was very remarkable. 



On the 16th and 17th I could see no tail through the equa- 

 torial, the nucleus being reduced to a mere hazy speck. The 

 length and brightness of the tail led me to expect a bright and 

 large nucleus ; but on the 6th, when it was first caught sight of 

 by Mr. Ellery, it was so faint as to leave some doubts as to its 

 identity. Mr. Ellery, in his telegram to me, says: — "Faint 

 nebulous point, perhaps nucleus, observed last night (the 6th) 

 E.A. 22° 48', dec, 32° 36'." 



The tail I considered was brightest on the evening of the 

 2nd, when I first saw it. It then appeared as a narrow auroral- 

 like streak of light, extending from the mists on the horizon, 

 perhaps a little N. of S.W., up to and passing nearly through 

 Delta 1 and Delta 2, and Beta Gruis, the upper extremity, from 

 about Delta Gruis, curving sharply to the south. On the fol- 

 lowing evening, the 3rd, clouds hung about the S.W., obscuring 

 the view ; but as they cleared off, the tail Avas well seen. It 

 was somewhat broader than on the 2nd, and perhaps a little 

 brighter than the Nubecula Minor, but not so bright as the 

 larger Magellan cloud. Roughly speaking, the tail had shifted 

 about 3° to the north, the stars Theta and Iota Gruis lying 

 on the northern edges of the tail, which in its curvature was 

 nearly concentric, with a line passing through Delta 1, Delta 2, 

 Beta, and JEpsilon Gruis, extending, as far as my eye could trace 

 it, to an altitude of about 27°. A low bank of cloud cut off the 

 view of the lower portion or head of the comet, which was pro- 

 bably not far from Beta Pisces Australis, at the time hid by 

 cloud. I see I made a note that the tail was brighter than on 

 the 2nd, but this I think was due to its greater altitude, its 



