100 



RECORD AND RESULTS OF 



The mean of four sets gives 1 vibration 6.4537 at 40° Fah. The vakie of m for 

 Z 1, as determined at Washington at 89°.7, = 0.2342, at 40° it becomes 0.2365; 

 we have also Ig (n'Ji-) = 1.19239 at 89°.7, and 1.19209 at 40°. Correcting for tor- 

 sion we find Ig mX= 9.57134 and X= 1.576. 



Port Foulke, Smith Strait. 



Observations at the Port Foulke Observatory. 



Set 1. Deflections. 3'' 39™ P. M., July 2, 1861. 



Magnet Z 1 suspended, Z 6 deflecting; distance 1.3 foot. 



Magnet. 

 E. 



W. 



Nortla end. 

 E. 



w. 



E. 



Circle. 

 38° 52' 

 38 54 



10 

 10 

 9 

 9 

 39 

 39 



00 

 04 

 40 

 42 

 29 

 26 



10" 



50 



40 



10 



40 



10 



10 



40 



Temperature. 

 40O.5 



39 



Moan 



39.8 



2m = 28° 51' 02' 



2m = 29 46 38 



; = 14 39 25 



Set 2. 



W. 



E. 



W. 



E. 

 W. 



E. 



76 



76 



335 



335 



338 



33 T 



76 



76 



Deflections. 



15 20 



17 00 



10 30 



09 20 



01 40 



59 30 



23 50 



26 40 



Distance 0.9 foot. 



15 20 



17 00 



11 00 



10 00 



02 00 



4" 38-^ 



60 



24 

 26 



20 

 00 

 40 



39 



38 



39.2 







Mean 



. 38.7 



Set 3. 



Deflections. 



Distance 1.0 foot. 



A. M. Ju 



E. 



26 44 



40 



45 00 



44.2 



" 



26 43 



20 



44 00 





W. 



318 19 



20 



20 00 





" 



318 19 



40 



20 20 



4.5.0 



" 



318 19 



40 



20 40 





" 



318 19 



40 



20 20 



43 



E. 



26 46 



20 



47 20 





" 



26 45 



20 



46 00 



43 



Mean 



43.8 



2m = 101 05 58 



2m = 98 24 26 



M= 49 52 36 



2m = 68 24 25 



2m = 68 26 20 



M= 34 12 41 



Torsion circle. 

 280° 30' 

 370 30 

 190 30 

 280 30 



Scale. 



300 



311.8 



292.0 



300.5 



Observations for Torsion. 

 Differences. 



11.8 



19.8 



8.5 



Mean (4) = 10.0 = 10'. 1 



W. 



Set' 

 E. 



W. 



Deflections. 



7° 47' 00" 



7 

 337 

 337 

 337 

 337 

 7 

 7 



47 

 19 

 19 

 25 

 25 

 53 

 53 



Distance 1.3 foot 



47' 20" 

 47 40 



20 

 20 

 26 

 26 

 54 

 54 



A. M. July 7, 1861. 

 42° 



Mean 



42 



41.6 



41.2 

 ^0 



41.4 



2 m = 30° 27' 15' 



30 28 10 



15 13 51 



