14 



REPORT ON 



Parallax . . . 4- o° o' 5". 3 



Reduction to meridian .......+ i 19.4 



Sun's declination ....... . — 19 6 59.1 



Latitude .......... 18 20' o" N. 



Circummeridian Altitudes of the Sun for Latitude, observed at Isle Royal, Salute Islands, 

 November 2%th, 1S65. 



13" 



57 s - 



125 5° 



3°' 



14 



35-5 



49 



"3° 



15 



9-5 



49 



3° 



15 



52 



49 



20 



16 



24-5 



48 



5o 



17 



i-5 



48 



40 



17 



38 



126 52 



10 



18 



i4-S 



5i 



10 



20 



17 



48 



20 



21 



9 



46 



10 



3 1 



46.5 



3° 







3 2 



3° 



26 



5o 



359 " 



2O 



' 2Q 



Index correction. 

 o° 16' 

 16 



359 



16 



Correction = + 16' 25". o 



Ex. ther. 

 At. ther. 

 Bar. 



91 



8 5 



30.13 inches. 



Mean of chronometer times . . .... . io h 



Chronometer slow of local mean time 1 



Equation of time . . . . . . . . + 



Local apparent time . . . . . . . .12 



Mean of observed double altitudes ..... 126 



Index correction . . . . . . . . + 



Apparent altitude of sun's centre 63 



Refraction . . . ■ . . . . . . — 



Parallax ,.........+ 



Reduction to meridian . . . . . . . + 



Sun's declination ....... . — 21 



Latitude 5 



37-9 

 19.4 

 42.6 

 39-9 

 55"-° 

 25.0 

 10. o 

 27.1 



3-9 

 35-7 



8-5 

 29" N. 



Observations for time were usually made in such a manner as to eliminate both 

 the sun's semi-diameter and all errors which might be produced by the roof of the 

 artificial horizon. For full details of the method see page 33 of the "Reports on 

 Observations of the Total Eclipse of the Sun, August 7, 1869," published by the 

 U. S. Naval Observatory, Washington. 



The reduction of the observations for time has been effected by means of the 

 following formula? : 



A + a 



r+P 



S: 



a -f- d -f- <?> 



¥ 



l/sin (S — a) cos S sec <p cosec d 

 dt = t + t — 1 



T = mean of observed chronometer times. 

 A = mean of observed double altitudes. 

 o = index correction. 

 r = refraction. _ 



p = parallax. 



