368 Astronomical and Nautical Collections. 



EXAMPLE. 



App. Z. D. = 87° 42' 10". Bar. 29.50. Therm. 35°. 

 Tab. I. 87°42'17 1.8160 Tab. I. 1.8160 



Tab. II. 35° A. C. 9.6961 Tab. II. 0.3039 



Tab. III. 0.2906 Log. Bar. 1.4698 



A 63',49 1.8027 Const. 7.2773 



B 7',36 0.8670 

 87°. 42,17 

 87 . 49,53 

 63,49 



11.2481 Tang. 86 . 46,04 (Z.D-A + B 

 Tab. II. 0.3039 



Log. Bar. 1.4698 



Refr. 1051 ",5 3.0218 



= 17' ,31"5 



[By the Nautical Almanac. 



Alt. 2° 17' 50' 

 2° 20' R. 17'. 0" Diff. 1' 4,1 6.35 Th. 2,8 

 8,9 2',10' + 8,9 50,-17,5 15°+42,0 

 42 

 17.50"i9 

 17,5 

 Tt^M : and if 48°, instead of 50°, were the 

 standard temperature of the table, it would be 17'. 27 ,8.] 



The mean of forty-two observations of a. Lyrae S. P. made at 

 the Observatory of Trinity College, Dublin, (mean of bar. 29,50, 

 and mean of therm. 35°) gave 17' 26",5 [: 5" less than Dr. 

 Brinkley's table ; 7" less than the N. A.]. 



If Table 2, Vol. XII., be added to them, they will serve for 

 computing the refraction from the zenith to the horizon. 



