Royal Astronomical Society. 577 



of a lever and a weight, which are brought into action for great al- 

 titudes, but which have no effect when the telescope is horizontal, 

 for preventing its flexure, and for securing its steady adjustment in 

 all positions. The effect of this the author describes as rendering 

 the images of stars equally round at all altitudes, and certainly never 

 better than when near the zenith. The declination and hour-circles 

 are each divided to 15', and by means of verniers can be read to 30" 

 and 2 s respectively. The polar axis is made in three parts. The 

 lowest part is a hollow cone of metal half an inch thick, the lower 

 end being solid, and turned into a ball 2 inches in diameter. The ' 

 ball is received into a nearly hemispherical brass step, provided with 

 adjusting-screws. The upper part of the cone is turned and driven 

 into the bored, internal surface of a cap-plate or flange, which af- 

 fords an attachment almost as firm as if the whole had been cast in 

 one piece. The exterior circumference of the collar of the flange is 

 also turned with great care, and rests on two cast-iron friction- 

 wheels, 7 inches in diameter, with axles of steel. The only bearings 

 of the motion in right ascension being the step at the foot of the 

 axis, and two points in the circumferences of the friction-wheels, the 

 motion is rendered very smooth, and the required impulse for motion 

 as small as can be desired. 



For observation of objects at great altitudes, a very simple con- 

 trivance is made to elevate the observer conveniently to the required 

 position at the eye-end of the telescope. Fastened to the following 

 side of the opening of the dome is a stiff bar of iron, notched in the 

 manner of a saw, upon which is hung, by iron hooks, a wooden 

 frame, in which a moveable foot-board is adjustable to different 

 heights, in the manner of the shelves of a bookcase, by which com- 

 bination of elevations every variety of altitude can be obtained, at 

 the same time that the sides of the frame afford an agreeable sup- 

 port to the observer. The operation of advancing the opening of 

 the dome, also carries on the observing-ladder, and the position of 

 the notched bar is such that the sliding of the ladder upon it, for 

 the most part gives the necessary variation in altitude, and is very 

 appropriately fitted to the change of position of the eye-tube of the 

 telescope. The object-end of the telescope and the declination- 

 circle are counterpoised by weights applied to the framework, not to 

 the telescope itself, by which it remains in equilibrio in all positions. 

 With a view of conveying as correct an impression as possible of the 

 general arrangement of the parts of the observatory and the instru- 

 ments, the author has accompanied his description by a model, on a 

 scale of one-tenth the full size in linear dimensions. 



Observations on Bremicker's Comet, with its apparent places, as 

 obtained, with the Equatoreal, at Mr. Bishop's Observatory, and 

 an account of the methods employed in deducing them. By the 

 Rev. W. R. Dawes. 



The extreme faintness of this comet rendering it observable only 

 by persons possessing large telescopes, Mr. Dawes was induced to 

 employ for the purpose Mr. Bishop's equatoreally-mounted telescope 

 of 7 inches clear aperture, and 10| feet focal length. The micro- 



