24 



MAGNETICAL OBSERVATIONS. 



Magnetic azimuth of the mark A. 

 1856. September 17, P. M. Theodolite and declinometer. 



CIBCLE TO THE BIGHT. 



Chronometer. 



Scale. 



Circle reading. 



Mean. 



gh 52m 



K 



Mark B 



Mark B 



7 3 

 K 



74.5 

 74.4 



74.4 



74 4 

 74.4 

 74.4 



280° 24' 



9.5 



15 



89 2 



1 



10 



89 1 



1 



10 



280 28.5 



13 



20 



280° 16'.; 



80 4.3 



+ 82.8 



89 4.0 



+ 32 3 



280 20.5 



Mean 



Bearinsc of A. 



N. 10° 39'.6 W. 

 10 44.2 



N. 10 41.9 W. 



Absolute magnetic declination. Magnetical azimuth of Mark A. 



1856. September 17, P. M. Theodolite and declinometer. 



CIRCLE TO THE LEFT. 



Ckronometer. 



R 



Mark B 



Mark B 



7 15 

 R 



Scale. 



Magnetical azimuth of mark A, N. 10° 40'.4 W. 



Horizontal intensity. Experiments of vibration. 



1850. September 17, P. M. Vibrating magnet D 3. 



No. 





 10 

 20 

 30 

 40 

 50 

 100 





 ]00 

 200 

 300 

 350 



Chronometer. 



45 

 45 

 46 

 46 

 46 

 49 



4P.8 

 7.9 



34.0 

 0.4 



26.8 



52. S 



3.8 



No. 



300 

 310 

 320 

 330 

 340 

 350 

 200 



Chronometer. 



57" 



58 



58 



59 



59 



59 



53 



48^0 

 14.4 

 40.8 

 70 

 33.3 

 59.2 

 20.4 



Time of 300 vibrations. 



13" 6^2 



6.5 

 68 

 6.6 

 6.5 

 6.4 



13 6.50 



Extreme scale readinj's. 



20 

 22.0 

 23.0 

 24.0 

 24.5 



40.0 

 38.0 

 .37.0 

 35.0 

 35.0 



Temperature 71°.9 F. 

 Time of 1 vibration 2^G217. 



