INVESTIGATIONS RELATIVE TO THE PROBLEM FOR 

 CLEARING THE APPARENT DISTANCE OF THE MOON 

 FROM THE SUN, OR A STAR, FROM THE EFFECTS OF 

 PARALLAX AND REFRACTION, AND AN EASY AND 

 CONCISE METHOD POINTED OUT. 



BY THE REV. J. BRINKLEY, D. D. F. R. S. & M. R. LA. 



ANDREWS PROFESSOR OF ASTRONOMY IN THE DIVERSITY OF DUBLIN. 

 — — »««eK^ S ^ «» »« ' ■ 



BEAD MARCH 7th, 1808. 



The importance of this problem in the practice of the 

 lunar method of finding the longitude at sea, affords a suf- 

 ficient excuse for the various solutions that have been offered. 

 Seamen require methods both concise, and not embarrassed 

 by distinction of cases ; they are often little able or willing 

 to practise any other. Of the two classes into Avhich the 

 solutions of this problem may be divided, the one in which 

 the correction of the distance is given and not the corrected 

 distance itself, is necessarily emban-assed by a distinction of 

 cases, although otherwise concise, as only requiring tables 

 to a few places of decimals. In the *other class are found 

 solutions which do not require any distinction of cases; 

 among such solutions, therefore, it should seem those are 

 to be selected which can be most readily adapted to practice 

 VOL. XI. . L by 



