44 



of light. It would have been extremely difficult to have 

 separated the compound results, and assigned the proper 

 quantity to each star, as Bradley was enabled to do at once, 

 as to his observations by his zenith sector. 



The observations I am about to state point out changes 

 of zenith distance in certain stars at difterent seasons of the 

 year, which changes are explained by annual parallax, and 

 after long and anxious consideration I have not been able to 

 assign any other cause. 



