ASTRONOMICAL AND GEODETIC OBSERVATIONS. 



37 



First position of pendulum. 

 Face i swinging, 86415. OT 

 " 2 " 86421.08 



Mean, 86418.08 



After reversal, end for end. 

 Face 1 swinging, 86422.45 

 " 3 " 86419.01 



Mean, 86420.'?6 



86419.42 

 .22 



Mean of two positions .......... 



Correction for 80' feet elevation above half tide + 



Resulting number of vibrations at the level of the gea in the latitude of Cambridge 86419.64 

 The Cambridge Observatory is in latitude 42° 22' 51 ".5 



Observations connected toitli Pendulum Experiments at Port Foidhe. 



The following observations for local time at Port Foulke were taken for the special 

 purpose of furnishing the chronometer rate required for the pendulum experiments. 

 The observed double altitudes of a Lyrte, September 22d and October 17th, 1860, 

 given in the preceding part of the astronomical record, belong to the same series. 



Observations for time, October 1, 1860. 



Double altitudes of a Lyra3, with reflecting circle. A. Sonntag, observer. 



T •, f+1'20" +1' 30" +1' 20"? ^ ,. , 1, 11,, K 



Index I +^ 00 +] 10 +1 50 5 Correction + 1' 11",1 



Pocket chronometer 

 10" 34" 08' 



35 20 



36 09 

 3T 08 

 38 08 



38 57 



39 57 



40 55 

 42 13 ' 

 48 08 



T= + 160.5, B = 29'".693 at 20° Index 



2* 





87° 53 



J40" 

 [30 



46 



UO 





(,10 



41 



[30 



[20 



35 



f30 



1.20 



30 



(40 



lio 



24 



(50 

 [40 



20 



(50 

 130 



15 



(20 



lio 



08 



(20 



lio 



01 



(60 

 [50 



Pocket clironometer 

 lO'' 44" 03^ 

 44 57 



46 04 



47 18 



48 09 



49 02 



49 44 



50 28 



51 55 



52 49 



+ 1' 10" +1' 20" +1' 20" 

 + 1 00 +1 00 +1 00 



2* 



86° 56' |JJ" 



51 1 2*^ 



^^ [00 



44 I'^O 



** [40 



37 ^° 



'^^ [30 



-> {To 



23 l**^ 



■^"^ 140 



19 1^^ 



^■^ j30 



" IS 



«^ {IS 



Corr'n + l' 08". 3 



(As in preceding cases, the observations were combined two by two.) 



Refi-'n for first pair — 1' 04". 7, for last —1' 06". 6 



»'s declination 6 = + 38"= 39' 35". 4, right ascension a = 18'' 32" 13'.9 



Sidereal time at mean noon 12'' 42" 33". 6 ; the sidereal time is converted into 

 mean time, and AT' is the chronometer correction on mean local time. 



• Annals of the Observatory, Vol. I, Part I, p. xvi. 



