ASTUONOMICAL AND GEODETIC OBSERVATIONS. 



15 



The following time observations were reduced for the purpose of comparing the 

 rates of the chronometers as found at Boston with rates determined at Port Foullte. 

 The chronometer corrections are known from observations of September 9th, and 

 of September 22d, 1860. 



Observations for time, September 22d, 1860. 

 Double altitudes of a Lyrse, with reflecting circle. 



4-0 50 { Correction -f 56. "7. 



Index 1 + 1' 10" +0'4O 

 inaex|_|_^ 20 +1 00 



Pocket chronometer. 



10" 43" 58^ 



10 45 55 



10 48 15 



10 49 45 



10 51 37 



10 52 48 



10 54 12 



10 55 23 



10 56 57 



10 58 20 



2*" 

 90° 12' 



Pocket ckronometer. 



90 02 



89 49 



f90" 

 150 

 [20 

 120 

 (20 

 (20 

 f40 

 (60 

 (10 

 (00 

 (40 

 (60 

 [20 

 (20 

 (50 

 (40 

 (50 

 t50 

 (20 

 1 10 

 Index between the two sets. 



f + 0' 40" +1' 10" +0'20") 

 1 + 50 +1 20 +0 30 j 

 Correction +48". 3 



T = + 20O.7, B = 29^72 at 58° 



r= — 61".6 andri = — 65".0 



6 = + 38° 39' 35". 1 



a= 18" 32" 14=. 2 



Sidereal time at mean noon 12" 07" 



40 



24 



17 



10 



02 



55 - 



11" 08"^ 



24= 







87 



°'' "(20 



^'-{11 



09 



29 









10 



35 









«ff 



11 



47 









=» {L» 



12 



40 









'^{fo 



14 



01 











15 



33 









" {11 



16 



50 









«'{t2 



17 



53 









» ill 



18 



45 







86 



^^{tt 



Index at the close ol 



'the 



; ob 



servations. 



(+0' 50" 



+ 1' 



20' 



' +1'20") 



t + 40 



+ 1 



10 





1 20 1 





Dorrc 



ction 



+ 66' 



.7 



04=. 7 



T 







h 



t 



aT 



10" 44" 



56=. 5 



450 



03' 17" 



+ 52° 39' 59" 



—50" 45' 



10 49 



00 



44 



51 57 



53 43 09 



—50 36 



10 52 



12.5 



44 



43 23 



54 30 33 



—50 40 



10 54 



47.5 



44 



36 25 



55 08 48 



—50 42 



10 57 



38.5 



44 



28 54 



55 49 48 



—50 50 



11 08 



56.5 



43 



57 14 



58 40 10 



—50 48 



11 11 



11 



43 



50 52 



59 14 02 



—50 47 



11 13 



20.5 



43 



44 26 



59 48 03 



—50 41 



11 16 



11.5 



43 



36 16 



60 30 55 



—50 41 



11 18 



19 



43 



30 15 



61 02 30 



—50 43 



Mean 



. _50 43.3 ± 0=.9 



Chronometer comparisons: Sej)tember 9, 1860. 

 Pocket chronometer. Mean time. 



Correction of 'pocket chronometer — 50" 

 Chronometers. a T 



35=1. 



2" 27" 2P.5 



1" 36" 46=.4 



2007: 6" 29" 



—4" 52" 13=. 6 



28 25.3 



1 37 50.2 



1062: 6 27 



—4 49 09.8 



29 05.5 



1 38 30.4 



740: 6 28 



—4 49 29.6 



