for the year 1882. xix 



been made both with the great reflector and the 8-in. refrac- 

 tor at the Observatory, and a remarkable character of nucleus 

 has been observed. On the 4th it was first seen to be of a 

 very long oval shape, central in the head, and its long axis 

 parallel with the general length of the tail. On the 6th 

 October it was observed to be inclined by several degrees 

 (5 degs. at least) from this parallelism, and to have a very 

 bright round and distinct planet-like spot in that part of the 

 nucleus nearest the head of the comet. On the 10th this 

 spot had moved nearer to the centre of the elongated oval 

 nucleus. The closeness of the dawn and subsequently strong 

 moonlight were much against spectroscopic observation of 

 its light until the 8th October, when I made a careful 

 examination of the nucleus and other parts of the comet. 

 The spectrum I found to consist of a moderately bright con- 

 tinuous spectrum, crossed by three broad bright bands, the 

 approximate wave lengths of whose centres were 5605, 5070, 

 4720, respectively. These bands were very bright in the 

 nucleus itself, and could be well seen anywhere near the head 

 of the comet, and traced faintly over a part of the tail for 

 some distance from the head. In the spectrum of Wells' 

 comet of 1881 several observers saw the well-known D line, 

 due to sodium — as far as I know a unique instance in the 

 case of cometic spectra. I examined carefully for any indi- 

 cation of this line in the present comet, but could discover no 

 trace. 



A series of observations for the determination of the solar 

 parallax indirectly by Dr. Galle's method has been made 

 with the 8-in. refractor. These observations consist in very 

 elaborate measures of differences of declination between the 

 small planets Victoria and Sappho and certain selected 

 fixed stars near them, taken each night between 18th July 

 and 18th October. Similar observations have been arranged 

 for in Europe, America, and at the Cape. A combination 

 of the results will furnish means for computing the parallax 

 of both these planetoids. The periodic times of these bodies 

 being known with great exactitude, it follows by Kepler's 



