125 



stance which acted on the mirror and produced a dulness that 

 was not removed till after three hours' additional work. Lord 

 Rosse warned them that the figure must be imperfect, and 

 wished to repolish ; but they overruled this proposal, and it 

 was replaced in the tube next day. 



On examining it by diaphragm and discs, it was found 

 that, as he anticipated, the edge was not quite perfect. All 

 its zones showed ^ Ursse Majoris very well with 560; but the 

 exterior six inches manifested, when the star was thrown out 

 of focus, that though of the same focal length, this portion was 

 irregular. Few other double stars were observed, as most of 

 the lucid interval from the 4th to the 13th of March was de- 

 voted to nebulae, and after that it again became cloudy; but 

 enough were seen to satisfy them that the instrument possessed 

 a very high defining power. This, indeed, was evident from 

 the admirable exhibition of Regulus, seen on March 5th, neat 

 and round, without appendages or flare. Gamma Leonis, £ 

 Virginis, 2 Comae, and Gamma Virginis, were also well 

 shewn with powers of 400 to 800 on an unfavourable night ; 

 and the companions of v Ursse, and 245 of Struve's second 

 Catalogue, which appear in the Slough and Pulkova teles- 

 copes as of the eleventh and tenth magnitudes, seem in this 

 large stars. 



Of planetary bodies, none were visible except D' Arrest's 

 Comet and the Moon. The former, when viewed March 

 10th, presented nothing remarkable: the brighter portion, to- 

 wards the centre, shewed no abrupt change of light which 

 might indicate a solid nucleus ; there was no resolvable ap- 

 pearance in the Coma, and the very minute stars with which 

 that part of the sky was dotted, were visible almost to its very 

 centre. Only one view of the moon was obtained, March 20th, 

 and it was shared with them by several visitors, who, when 

 once in possession of the telescope, were by no means disposed 

 to make way for the astronomers. The fascination of the 

 sight is, indeed, such, that one can scarcely withdraw the eye: 



