no IN STARRY REALMS. 



Thus a record is obtained which makes the closest ap- 

 proach to absolute precision. 



But for the purposes of the continuous observation of a 

 celestial body the meridian instrument is quite unfitted. 

 It merely gives us a flying glimpse of the object as it 

 hurries through the field ; a glimpse sufficient for the 

 determination of the place of the object, but quite inade- 

 quate to enable us to examine the object with any close 

 attention. A totally different form of mounting for our 

 telescope is now required, which shall enable us to follow 

 the object persistently for hours together. Of course the 

 facility of movement in the telescope which this implies 

 can only be obtained by the sacrifice of some other 

 qualities. The equatorial for so this form of mounting 

 is termed is quite unsuited for the rigidly accurate pur- 

 poses of measurement, which it is the sole object of the 

 meridian circle to obtain. In the stand of the equatorial 

 clockwork is placed, by which the instrument, after it has 

 been once pointed to the star, is constrained to move so 

 that the object under examination shall continue steadily 

 in the field of the observer's view. 



It is the equatorial that we are to visit when we come 

 to spend our evening at the observatory. "We shall find 

 ourselves usually in a circular room covered by a dome. 

 This dome reposes on wheel work, so that it can be made 

 to revolve. In it is a shutter, which can be opened so as 

 to allow the telescope to be pointed to the sky. There is, 

 of course, no glass window in the opening ; even the most 

 transparent plate glass would impair the perfection of 

 the image. Nor will it be allowable to have the building 

 warmed by artificial heat. If the temperature inside 



