30 



observatories of Greenwich and Armagh, I shall give an ex- 

 ample at length, of the deduction of the longitude in each 

 method ; and also a short table of the actual apparent differ- 

 ences of AR. of the principal fixed stars, observed on the 

 same dajs at Greenwich and Armagh, that every reader may 

 thus judge of the eligibility of each different method, and, 

 also, clearly see the degree of precision to be expected from 

 such observations, in which various observers, different time- 

 pieces, and transit instruments, generally of different pow- 

 ers, are necessarily concerned, when made with due degrees 

 of care and skill in the adjustments, application and use 

 of such instruments. 



EXAMPLE. 



