RESULTS OF THE MAGNETICAL OBSERVATIONS. 



MAGNETIC DECLINATION. 

 Station No. I. Vera Cruz. 



Magnetic azimuth of tlie mark A 

 Astronomical " " " 



Magnetic declination, 1856, August 7, at noon 



Station No. II. Potrero. 



Magnetic azimuth of the mark A . 

 Astronomical " u a 



Magnetic declination, 185G, August 17, 7'' 13'" A. M. 



Station No. III. Cocolapam near Orizaba. 

 Magnetic azimuth of the mark A . 

 Astronomical " " « 



Magnetic declination, 1850, August 27, 10'' 8™ A. M. 



Station No. IV. San Andres Chalchecomula. 

 Magnetic azimuth of the mark A . 

 Astronomical " << '< 



Magnetic declination, 1850, September 17, 0'' 40"' P. M. 



Station No. V. Mirador. 



Magnetic azimuth of the mark A , 

 Astronomical " " " 



Magnetic declination, 1850, October 10, 7'' 12'" A. M. 



Station No. VI. City or Mexico. 



Magnetic azimuth of the mark A . 

 Astronomical " << << 



Magnetic declination, 1856, December 11, 10'' 19'" A. M. 



Station No. VIII. Kancho Tlamaoas. 



Magnetic azimuth of the mark A . 

 Astronomical " " « 



Magnetic declination, 1857, January 25, l"" 19™ P. M. 



N. 52° lO'.S \\. 

 N. 44 2 9 W. 



8 10.9 E. 



N. 83° 2'.8 W. 

 N. 74 23.G W. 



8 39.2 E. 



N. 79° 32'.8 E. 

 N. 88 1.1 E. 



8 28.3 E. 



N. 10° 40'.4 W. 

 N. 2 27.0 W. 



8 12.8 E. 



N. 101° 49'.7 E. 

 N. 109 51.3 E. 



8 1.6 E. 



N. 106° 22'. 6 W. 

 N. 97 36.1 W. 



8 46.5 E. 



N. 145° 7'.3 E. 

 N. 153 35.7 E. 



8 28.4 E. 



HORIZONTAL INTENSITY. 



The constants K and g for the magnet D 3, which was exclusively used in the experiments of vibrations 

 and deflections, had been determined in 1855 by Mr. Chas. A. ScnoTT, U. S. Coast Survey, and found: — 

 Moment of inertia A' =2.0072, at temperature 76°. 2. 

 CoefiScient of temperature g = 0.00022. 



