ASTRONOMICAL AND GEODETIC OBSERVATIONS. 67 





Clironometer 



Corr'n 



Mean time 



No. of 



Corresp. No. 



Corrections for 



N. 







intervals. 



for rate. 



intervals. 



vib'ns. 



in a day. 



arc. 1 temp, latm.pr. 













Set 16. 



Face 1 



October 



11. 



L. 



4" 



20"' 



59'.08 



— =.82 



15658^26 



15688 



86564.10 



+ .79 



—12.11 



.00 



86552.78 



R. 



4 



21 



00.82 



— .82 



15660.00 



15690 



65.50 



.76 







54.15 



L. 



4 



21 



09.04 



— .82 



15668.22 



15698 



64.20 



.72 







52.81 



R. 



4 



21 



06.96 



— .82 



15666.14 



15696 



64.68 



.69 







53.26 



L. 



4 



20 



37.02 



— .82 



15636.20 



15666 



64.66 



.64 







53.19 



R. 



4 



20 



3Y.02 



— .82 



15636.20 



15666 



64.66 



.61 







53.16 



L. 



4 



20 



35.10 



— .82 



15634.28 



15664 



64.22 



.58 







52.69 



R. 



4 



20 



39.00 



— .82 



15638.18 



15668 



64.76 



.55 







53.20 



Mean . 



86553.15 













Set 17. 



Face 3 



October 



12. 



li. 



4 



23 



09.35 



— .88 



15788.47 



15818 



86561.60 



+ .67 



—18,24 



—.15 



86548.88 



R. 



4 



23 



15.51 



— .88 



15794.63 



15824 



60.68 



.64 







48.93 



L. 



4 



23 



15.25 



— .88 



15794.37 



15824 



62.08 



.61 







49.30 



R. 



4 



23 



13.26 



— .88 



15792.38 



15822 



62.04 



.59 







49.24 



L. 



4 



23 



11.24 



— .88 



15790.36 



15820 



62.18 



.55 







49.34 



R. 



4 



23 



13.39 



— .88 



15792.51 



15822 



61.32 



.53 







48.46 



L. 



4 



23 



11.32 



— .88 



15790.44 



15820 



61.74 



.52 







48.87 



R. 



4 



22 



57.42 



— .88 



15776.54 



15806 



61.32 



.50 







48.43 



Mean . 



86548.93 



We therefore have the following resulting number of vibrations performed at 

 Port Foulke in a mean solar day, the temperature of the pendulum being at 50° 

 Fah., and the atmospheric pressure 29.8 inches (with the mercury at the tempera- 

 ture of freezing water). 



First position of pendulum. 

 Face 4 swinging, 86550.17 

 Face 2 " 86549.28 



After reversal end for end. 

 Face 1 swinging, 86551.81 

 Face 3 swinging, 86551.18 



Mean, 86549.72 Mean, 86551.50 



Mean of two positions ........ 86550.61 



Correction for 40 feet elevation above balf tide . . . +0.11 

 Resulting number of vibrations at tlie level of the sea in the 



latitude of Port Foulke . . . . . . . 86550.72 



The Fort Foulke Observatory^ is in latitude ... 78° 17' 39" 



At Cambridge we have an excess of 2.68 vibrations in a day in the second position 

 when compared with the first; at Port Foulke this excess is 1.78 vibration, from 

 which numbers we infer that the pendulum has undergone no change. 



Finally we have from the relation oi g : gi=W : N^^ force of gravity at Cam- 

 bridge to force of gravity at Port Foulke as (86419.64)" to (86550.72)^; however, 

 if we reject the number of vibrations at Cambridge, face 4 swinging, as too small, 

 since at Port Foulke the number for this position is quite accordant with the num- 



