MAGNETIC OBSERVATIONS. 



17 



Chronometer slow of local mean time. . . . . i h 30™ ig 8 .4 



Longitude west 3 30 n. 4 



5 ° 3°- 8 



Chronometer slow of Greenwich mean time 



Double Altitudes of the Sun for Time, observed at Ceara, Brazil, December i$th, 1865. 



I5 m 



i3"-5 



63 



15 



58-5 



62 



16 



41 





17 



3-5 





17 



26 



62 



18 



43 



62 



19 



5 





19 



26.5 





*9 



5° 



62 



20 



"•5 



61 



Index correction. 



3° 



5° 



2O 



2Q 



At. ther. 



359° 



11' 

 10 

 10 



0' 



5° 

 40 





0° 



16' 



0" 



10 







359 



10 



5°- 











16 



3-3 



Ex. ther. 84 

 Refraction = — 89". 5 

 Parallax ■— + 7-4 



Mean of observed double altitudes 

 Mean of chronometer times 

 Equation of time 



Correction = + 16' 33". 3 



82 Bar. 30.05 inches. 



Sun's declination — 23 12' 4".o 



. 62 18' o".o 

 . i h i7 m 57 8 -8 

 .— 5 20.9 



Reducing this observation with latitude = — 3° 43' 15", we find the chronometer 

 2 h 26 m 29 3 .6 slow of local mean time. Reducing it with latitude = — 3° 44' 15", 

 we find the chronometer 2' 1 26'" 32 s .O slow of local mean time. 



Double Altitudes of the Sun for Time, observed at Ceara, Brazil, December 14th, 1865. 



2 1 " 



°"-5 



2 



24-5 



2 



49 



3 



12.5 



3 



36 



6 



9 



6 



32-5 



6 



57-5 



7 



21-5 



7 



45-5 



99 3° 



40 



5° 

 100 o 



10 

 100 10 



20 



3° 



40 



100 50 



Ex. ther. Si° 

 Refraction = — 45"-9 

 Parallax = + 5.6 



Index correction. 



2Q 



359° 



10' 



3° 



40 

 40 



o° 



16' 



10' 



20 

 20 





359 



10 



36-7 







16 



16. 



7 



At. ther. 82 



Sun's declination 



Correction = + 16' 33". 3 

 Bar. 30.12 inches. 



Mean of observed double altitudes 

 Mean of chronometer times 

 Equation of time 



14' 46". 2 



. 100 10 o .0 



• 7" 4 m 52"-8 

 •— 4 59-5 



Reducing this observation with latitude = — 3° 43' 15", we find the chronometer 

 2 h 26 m 33 3 .7 slow of local mean time. Reducing it with latitude = — 3° 44' 15", 

 we find the chronometer 2 h 26 m 30 3 .9 slow of local mean time. 



February, 1872. 



