200 Comet II. 1862. 



when even the comparatively well-marked features of Donates 

 Comet have met with discordant delineation at the hands of 

 such men as Struve, Bond, Secchi, Lassell, Dawes, and De La 

 Rue, it cannot, in fairness, be expected that any set of repre- 

 sentations should be found in perfect agreement with others, 

 especially under unequal circumstances as to optical power and 

 transparency of atmosphere. 

 My first observation was on 



August 14, in strong moonlight ; when the nucleus had 

 the aspect of a small star, with powers of 55 and 170, but 

 became diffuse with 460. The coma was unequally distributed 

 around it, being accumulated towards the sun ; in this direc- 

 tion a dim and ill-defined brush of light issued from the nucleus, 

 which was not effaced with 460. The tail, which was short 

 and faint, issued chiefly from the left (inverted) side of the 

 coma, giving an irregular aspect to the head, as though the 

 axis of greatest brightness made an angle of 30° or 40° with 

 that of the tail. 



August 18. A clear night, but tremulous definition. The 

 comet is a noble object in the comet eye-piece, power 27. The 

 extent of the coma is very indefinite, but from a comparison 

 with the diameter of the field may be put down at 15'. The 

 tail can be traced with this eye-piece about 3^°, it rises from 

 little more than one-half, or perhaps two-thirds of the coma, 

 on the left inverted, or diurnally preceding, or orbitally follow- 

 ing side ; towards which side its edge is sensibly concave, as 

 well as brightest and best defined. Its breadth at its origin 

 may be 10'; at a distance of 1° from the nucleus, about 22'. Its 

 structure is streaky some way from the head, but there is no 

 central darkness. Nucleus stellar with 55, 82, and 110; 170 

 begins to show a hazy border ; 460 confuses it ; its diameter 

 may be estimated, very uncertainly, 1" or 2". A ray issues 

 from it to the left, not centrally or directly, but with a kind of 

 twist at its origin, the nucleus being in a line with its lower 

 (inverted) edge ; so that we have a kind of reduced copy of the 

 whole comet in its own interior. 27 shows this ray, but it is 

 much more distinct with 55 and 82, and is still evident with 

 170 and even 460. No clearly marked trace of an envelope, 

 but something like a feeble sector of light, best seen with 27 : 

 the direction of the right side of the tail being assumed as 0°, 

 its commencement may be fancied about 150 1 : thence it seems 

 to advance, as to the vertex of a parabola, towards the sun ; 

 receding on the other side, it encounters the ray at about 

 210'', and is merged in the general light of the coma somewhere 

 near 270°. All this is exceedingly indistinct ; but it is more 

 evident that there is a difference of hue, giving a particoloured 

 and patchy aspect to the head; the nucleus and ray being 





