.53 



Capella, /3 Tauri Procyon, Polaris, above and below the 

 pole, y Draconis, (3, ^, ti, Ursae majoris and other stars do not 

 shew changes of zenith distance similar to what appear as to 

 a Lyrae, Arcturus, «, Aquilaj, * Cygni, and a, Ophiuchi. 



The mean zenith distances from a number of observations 

 of the pole star above and below the pole are given, as in- 

 stances where no changes of zenith distance are noticed. * 

 Also the results as to « Aquiloe, Arcturus and « Cygni. The 

 results as to other stars which seem to have a sensible pa- 

 rallax will be given when the observations are more nu- 

 merous. 



If parallax be not admitted, it must appear very remarka- 

 ble that in no stars have annual changes of zenith distance 

 been observed by this instrument that cannot be explained 

 by a parallax. It might be expected that in some stars the 

 changes would have been quite opposite to the changes from 

 parallax. 



It may perhaps be suggested that there may be some un- 

 known peculiarity in my mode of observing, that would ex- 

 plain these appearances of parallax. In answer to this it is 



* In the observations of the pole stat, each zenith distance is the result of observa- 

 tions made before and after the meridian passage of the star, the instrument having been 

 reversed in the interval. This has sometimes been done for other stars, but not often. 

 Tlie value of this instrument may be considered as much enhanced from being capable 

 of being used at a small distance on each side of the meridian, by noting the time of 

 observation. 



