New Reflecting Telescope and Observatory. 213 



are 2oin. diameter, the verniers reading to seconds and ten 

 seconds respectively. Other considerable improvements 

 introduced by Mr. Calver into the construction are seen in 

 the driving clock, arranged to beat seconds when required 

 on a small bell and with maintaining power to keep it going 

 whilst being wound up ; also in its direct connection with 

 the hour circle. The clock is arranged to drive the hour 

 circle continuously without carrying the telescope, and thus 

 the hour setting can be done once for all to sidereal time for 

 a whole night's work. Thus only right ascension setting is 

 needed in finding any object, and, when found, the half turn 

 of a handle attaches the telescope to the hour circle, and it 

 is also carried along by the clockwork and the object is held 

 centrally in the field of the eyepiece. There is also a special 

 hand slow motion that can be applied without stopping the 

 clock, either to accelerate or "retard the motion, or to enable 

 the observer to examine different portions of a large object 

 without affecting the clock driving. This and a similar slow 

 hand motion in declination are both brought up to, and can 

 be applied from, the eyepiece by the observer, as occasion 

 may require. 



The various eyepieces provide magnifying powers ranging 

 from 70 to 1,000 diameters. The performance of the tele- 

 scope, so far as at present tested, is very satisfactory ; obser- 

 vations on the Moon, Saturn, the great Nebulae in Orion, 

 double stars, &c, have been made, and show how much may 

 be expected from this noble instrumentwhen the adjustments 

 are completed, and good observing nights are obtained. 



The observatory built for this telescope also presents 

 some novel points in construction. The objects sought 

 were, in the first place, to obtain a cheap and efficient 

 structure, and secondly, one which would not require any 

 great power to manipulate in moving the dome and shutter, 

 which in so large a size would have required special arrange- 

 ments if made in the ordinary way. The dome is composed 



